Resist lower layer film-formed substrate

ABSTRACT

A resist lower layer film composition, wherein an etching speed is fast, thus an etching time period can be shortened to minimize a film thickness loss of a resist pattern and a deformation of the pattern during etching, therefore, a pattern can be transferred with high accuracy and an excellent pattern can be formed on a substrate is provided. 
     The resist lower layer film composition comprising at least a polymer having a repeating unit represented by the following general formula (1).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a resist lower layer film compositionfor a multilayer resist film used for microfabrication in a process formanufacturing semiconductor devices etc., and particularly relates to aresist lower layer film composition suitable for exposure by farultraviolet ray, KrF excimer laser light (248 nm), ArF excimer laserlight (193 nm), F₂ laser light (157 nm), Kr₂ laser light (146 nm), Ar₂laser light (126 nm), soft X ray, an electron beam, an ion beam, X rayand the like. Furthermore, the present invention relates to a patterningprocess for patterning a substrate using the resist lower layer filmcomposition with lithography.

2. Description of the Related Art

In recent years, with advanced high integration and speed up of LSI, ithas been required to make a pattern rule finer. In such a circumstance,in lithography using light exposure currently used as common technology,an essential resolution derived from a wavelength of a light source hasbeen approaching a limit.

There is widely used optical exposure using g line (436 nm) or i line(365 nm) of a mercury-vapor lamp as a light source for lithography whena resist pattern is formed. It has been considered that a method ofusing an exposure light with a shorter wavelength is effective as ameans for obtaining a further finer pattern. For this reason, forexample, KrF excimer laser (248 nm) with a shorter wavelength is used asan exposure light source instead of i line (365 nm) for mass-productionprocess of a 64 M bit DRAM processing method. However, a light sourcewith far shorter wavelength is needed to manufacture DRAM withintegration degree of 1 G or more which needs still finer processingtechniques (for example, a processing size is 0.13 μm or less).Accordingly, lithography with ArF excimer laser (193 nm) has beenparticularly examined.

As the resist film has been made thinner, materials capable of beingetched at a considerably higher speed are required for ordinary organicantireflection films compared with the resist. The organicantireflection film where the etching speed is enhanced by changing abase resin from a novolak type to a (meth)acryl type and further to apolyester type has been developed.

In the resist pattern after the exposure and the development on a masksubstrate of Cr and the like, in the positive type photoresist, aproblem that a substrate interface becomes a footing profile hasoccurred. It is believed that this is caused by diffusing the acidgenerated in the photoresist due to the exposure in the mask substrateof Cr or the like to reduce an acid concentration in the photoresistnear the substrate. In order to reduce the occurrence of the footingprofile, the improvement has been performed by using a protecting grouphaving a low activation energy for a deprotection reaction with theacid, but this is not sufficient. To reduce the occurrence of thefooting profile, it is effective to use an organic film between thephotoresist and the Cr substrate.

An antireflection function is necessary in the case of the opticalexposure, but in depiction of the mask pattern, the antireflectionfunction is not particularly needed because the electron beam (EB) isused. Required are an excellent acid block function and a high etchingspeed for not diffusing the acid generated in the photoresist to thesubstrate.

Here, a resist lower layer material containing a polymer havingα-hydroxymethyl acrylate as a repeating unit is disclosed (see Japanesepatent Lapid-open (Kokai) No. 2007-17949). However, an organic filmwhich has the higher etching speed has been required.

SUMMARY OF THE INVENTION

The present invention has been accomplished to solve the above-mentionedproblems, and an object of the present invention is to provide a resistlower layer film composition for a monolayer resist process and amultilayer resist process, which can also be used as an antireflectionfilm composition suitably, has a high dry etching speed and thus canshorten an etching time period to prevent a film loss and atransformation of an upper layer resist film, and a patterning processfor patterning a substrate by using the resist layer film compositionwith lithography.

The present invention has been accomplished for solving theabove-mentioned problems, and provides a resist lower layer filmcomposition comprising: at least a polymer having a repeating unitrepresented by the following general formula (1),

wherein R¹ represents a hydrogen atom or a methyl group; R² represents alinear or branched alkylene group having 1-8 carbon atoms; R³ representsa hydrogen atom or an acid labile group; and 0<a≦1.0.

On the resist lower layer film formed from such a resist lower layerfilm composition, the dry etching speed is fast in transfer of a resistpattern after development. Thus, the dry etching time period can beshortened and the film loss of the upper layer resist film during thedry etching can be minimized. Therefore, the resist pattern can betransferred with high accuracy, and an excellent pattern can be formed.

In this case, the resist lower layer film composition may serve as anantireflection film composition.

This way, the resist lower layer film composition can be used as anantireflection film composition in photolithography. The resist lowerlayer film formed from this serves as the antireflection film, and thus,a halation and a stationary wave caused by reflection upon exposure canbe inhibited to form an excellent resist pattern.

The polymer can further comprise a repeating unit having a lightabsorbing group of an aromatic group.

The aromatic group is highly light-absorbable, and if an antireflectionfilm composition comprising such a polymer is used, the antireflectionfilm having an appropriate antireflection function can be formed.

It is preferable that the resist lower layer film composition furthercontains one or more of an organic solvent, an acid generator and acrosslinking agent.

If the resist lower layer film composition further contains the organicsolvent, an application property of the resist lower layer filmcomposition can be further enhanced. If the resist lower layer filmcomposition further contains one or more of the acid generator and thecrosslinking agent, a crosslinking reaction in the resist lower layerfilm can be facilitated by baking after applying on the substrate.Therefore, a dense film can be obtained, there is little possibility ofintermixing with the resist upper layer film, and there is few diffusionof low molecular components into the resist upper layer film or thelike. As a result, an excellent resist pattern can be obtained, and anexcellent pattern can be formed on the substrate.

It is preferable that the acid generator is an ammonium salt representedby the following general formula (2),

wherein R^(101d), R^(101e), R^(101f) and R^(101g) each represent ahydrogen atom, a linear, branched or cyclic alkyl, alkenyl, oxoalkyl oroxoalkenyl group having 1-12 carbon atoms, an aryl group having 6-20carbon atoms, or an aralkyl or aryloxoalkyl group having 7-12 carbonatoms where a part of or all of hydrogen atoms may be substituted with aalkoxy group(s); R^(101d) and R^(101e), or R^(101d), R^(101e) andR^(101f) may form a ring, and when forming the ring, R^(101d) andR^(101e), or R^(101d), R^(101e) and R^(101f) each represent an alkylenegroup having 3-10 carbon atoms or a heteroaromatic ring having anitrogen atom in the formula in the ring; and K⁻ represents anon-nucleophilic counter ion.

This way, when the acid generator is the ammonium salt, substancesgenerated by thermal decomposition are amine and an acid. Thus, they areevaporated by heat and unlikely to become a source of particleformation. Therefore, there is little possibility of contaminating thesubstrate upon forming the pattern, and the substrate with highcleanliness can be obtained.

The present invention also provides a patterning process for patterninga substrate with lithography, wherein at least, a resist lower layerfilm is formed on the substrate using the resist lower layer filmcomposition, a photoresist film is formed on the resist lower layerfilm, a pattern circuit area of the photoresist film is exposed and thendeveloped with a developer to form a resist pattern on the photoresistfilm, and the resist lower layer film and the substrate are etched usingthe resist pattern as a mask, to form a pattern on the substrate.

This way, an excellent pattern can be formed on the substrate by placingthe resist lower layer film formed using the resist lower layer filmcomposition between the substrate and the photoresist film.

The present invention also provides a patterning process for patterninga substrate with lithography, wherein at least, an organic film isformed on a substrate, a silicon-containing film is formed on theorganic film, a resist lower layer film is formed on thesilicon-containing film using the resist lower layer film composition, aphotoresist film is formed on the resist lower layer film, a patterncircuit area of the photoresist film is exposed and then developed witha developer to form a resist pattern on the photoresist film, the resistlower layer film and the silicon-containing film are etched using theresist pattern as the mask, the organic film is etched using thesilicon-containing film on which the pattern is formed as a mask, andthe substrate is further etched, to form a pattern on the substrate.

This way, a pattern may formed on the substrate by forming the organicfilm and the silicon-containing film on the substrate and placing theresist lower layer film formed using the resist lower layer filmcomposition between the silicon-containing film and the photoresistfilm.

As described above, the resist lower layer film composition of thepresent invention comprises as a base resin at least the polymer havingthe repeating unit of (meth)acrylic ester represented by the generalformula (1) having a hexafluoroalcohol group or a substituent thereof,has fluorine atoms and abundantly comprises oxygen atoms compared withmethacrylate usually used. Thus, the etching speed is fast. Therefore,the etching when the resist pattern after the development is transferredto the substrate can be performed in a short time, and the film loss ofthe upper layer resist film and a deformation of the pattern can beminimized. Accordingly, the resist pattern can be transferred with highaccuracy, and an excellent pattern can be formed on the substrate.

DESCRIPTION OF THE INVENTION AND A PREFERRED EMBODIMENT

Embodiments of the present invention will be described below, but thepresent invention is not limited thereto.

If the etching speed on the resist lower layer film is slow, the etchingfor transferring the resist pattern after the development to thesubstrate takes a long time to cause the film loss of the upper layerresist film and the deformation of the pattern. Thus, an excellentpattern can not be formed on the substrate. Therefore, it is necessarythat the etching speed on the resist lower layer film is faster thanthat on the upper layer resist film.

In order to make the etching speed faster, it is important to reduce acarbon density. Thus, the etching speed has been enhanced by changingthe base polymer in the antireflection film from the novolak type to the(meth)acryl type and further to the polyester type to increase a ratioof oxygen and decrease a ratio of carbon.

However, it could not be said yet that the etching speed on theconventional resist lower layer film composition was sufficiently fast.

Thus, the present inventors studied extensively to develop the resistlower layer film composition exhibiting the faster etching speed.

In F₂ resist, a transparency at a wavelength of 157 nm was enhanced byintroducing fluorine, but the reduction of etching resistance has beenpointed out. From this, the present inventors thought of that theetching speed could be enhanced by introducing fluorine.

From the above, the present inventors have thought of that when a resistlower layer film composition comprises at least a polymer having(meta)acrylic ester as a repeating unit having a hexafluoroalcohol groupor one obtained by substituting its hydroxy group with an acid labilegroup, a resist lower layer film formed from the resist lower layer filmcomposition has a good adhesiveness to a resist, can produce not afooting profile or a conversely tapered shape but a perpendicular shapeof a photoresist pattern after the development, can shorten an etchingtime period because an etching speed is fast and can inhibit a filmthickness loss of the photoresist by the etching, and have completed thepresent invention.

That is, the resist lower layer film composition of the presentinvention comprises: at least the polymer having the repeating unitrepresented by the following general formula (1),

wherein R¹ represents a hydrogen atom or a methyl group; R² represents alinear or branched alkylene group having 1-8 carbon atoms; R³ representsa hydrogen atom or an acid labile group; and 0<a≦1.0.

The resist lower layer film composition of the present invention has afeature that the etching speed is fast. This feature is accomplished bymaking R² not a cyclic but a linear or branched alkylene group,containing fluorine atoms in the repeating unit a and containing oxygenatoms more abundantly compared with methacrylate usually used.

Since the resist lower layer film composition of the present inventionhas the fast etching speed, the etching time period for transferring theresist pattern can be shortened and the film loss of the upper layerresist film due to the etching can be inhibited.

Therefore, the resist pattern can be transferred with high accuracy, andan excellent pattern can be formed.

The resist lower layer film composition of the present invention can beused for forming the antireflection film for preventing the halation andthe stationary wave in photolithography, and can also be used forforming the resist lower layer film for preventing the occurrence of thefooting profile and an undercut of the resist in electron beam exposure.

The method for synthesizing the polymer having the repeating unitrepresented by the general formula (1) is not particularly limited, andcan be performed by standard methods.

The monomer for obtaining the repeating unit a in the general formula(1) is not particularly limited, and is exemplified as follows.

(In the formulae, R¹ and R³ are the same as defined above.)

As shown in the general formula (1), the repeating unit a has thehexafluoroalcohol group or the group obtained by substituting itshydroxy group with the acid labile group. By substituting with the acidlabile group, a hydrophobicity can be enhanced and the hexafluoroalcoholgroup can be actively oriented to a surface direction of the film. Theacid labile group deprotects by crosslinking with acid to convert intohighly hydrophilic hexafluoroalcohol, thereby enhancing the adhesivenessto the resist and preventing the occurrence of blob defect on theantireflection film after the development.

Here, as the acid labile group represented by R³ in the general formula(1), various ones are selected, they may be the same or different, andgroups represented by the following formulae (AL-10) and (AL-11), atertiary alkyl group having 4-40 carbon atoms represented by thefollowing formula (AL-12), an oxoalkyl group having 4-20 carbon atoms,and the like are included.

In the formulae (AL-10) and (AL-11), R⁵¹ and R⁵⁴ represent a monovalenthydrocarbon group such as a linear, branched or cyclic alkyl grouphaving 1-40, in particular 1-20 carbon atoms, which may contain heteroatom(s), such as oxygen, sulfur, nitrogen, or fluorine. R⁵² and R⁵³represent a hydrogen atom, or a monovalent hydrocarbon group such as alinear, branched or cyclic alkyl group having 1-20 carbon atoms, whichmay contain hetero atom(s), such as oxygen, sulfur, nitrogen, orfluorine. a5 is an integer of 0 to 10. R⁵² and R⁵³, R⁵² and R⁵⁴, or R⁵³and R⁵⁴ may be linked to form a ring having 3-20, in particular 4-16carbon atoms with the carbon atom to which R⁵² and R⁵³ bond or thiscarbon atom and the oxygen to which R⁵⁴ bonds.

R⁵⁵, R⁵⁶ and R⁵⁷ independently represent a monovalent hydrocarbon groupsuch as a linear, branched or cyclic alkyl group having 1-20 carbonatoms, which may contain hetero atom(s), such as oxygen, sulfur,nitrogen, or fluorine. R⁵⁵ and R⁵⁶, R⁵⁵ and R⁵⁷, or R⁵⁶ and R⁵⁷ may belinked to form a ring having 3-20, in particular 4-16 carbon atoms withthe carbon atom to which R⁵⁵, R⁵⁶, and R⁵⁷ bond.

Illustrative examples of the compound represented by the formula (AL-10)may include: tert-butoxy carbonyl group, tert-butoxy carbonyl methylgroup, tert-amyloxy carbonyl group, tert-amyloxy carbonyl methyl group,1-ethoxy ethoxy carbonyl methyl group, 2-tetrahydropyranyl oxy-carbonylmethyl group, 2-tetrahydrofuranyl oxy-carbonyl methyl group, and thelike, and further the substituents represented by the following generalformulae (AL-10)-1 to (AL-10)-10.

In the formulae (AL-10)-1 to (AL-10)-10, R⁵⁸ may be the same ordifferent, and represents a linear, branched or cyclic alkyl grouphaving 1-8 carbon atoms, an aryl group having 6-20 carbon atoms or anaralkyl group having 7-20 carbon atoms. R⁵⁹ represents a hydrogen atom,or a linear, branched or cyclic alkyl group having 1-20 carbon atoms.R⁶⁰ represents an aryl group having 6-20 carbon atoms or an aralkylgroup having 7-20 carbon atoms. a5 represents the same as explainedabove.

Examples of an acetal compound represented by the formula (AL-11) mayinclude those represented by the formulae (AL-11)-1 to (AL-11)-34.

Intermolecular crosslinking or intramolecular crosslinking in the baseresin may be performed by the acid labile group represented by thegeneral formula (AL-11a) or (AL-11b).

In the above formulae, R⁶¹ and R⁶² represent a hydrogen atom or alinear, branched or cyclic alkyl group having 1-8 carbon atoms.Alternatively, R⁶¹ and R⁶² may be linked to form the ring together withthe carbon atoms to which R⁶¹ and R⁶² are bound. When the ring isformed, R⁶¹ and R⁶² represent a linear or branched alkylene group having1-8 carbon atoms. R⁶³ represents a linear, branched or cyclic alkylenegroup having 1-10 carbon atoms. b5 and d5 represent an integer of 0 or 1to 10, preferably 0 or 1 to 5, and c5 represents an integer of 1 to 7. Arepresents a (c5+1) valent aliphatic or alicyclic hydrocarbon group, anaromatic hydrocarbon group or a heterocyclic group having 1-50 carbonatoms, these group may have hetero atom(s) such as O, S and N, and apart of the hydrogen atom(s) bound to the carbon atom(s) of A may besubstituted with a hydroxyl group, a carboxyl group, a carbonyl group orfluorine atoms. B represents —CO—O—, —NHCO—O— or —NHCONH—.

In this case, preferably A represents a bivalent to quadrivalent linear,branched or cyclic alkylene group, alkyltriyl group, alkyltetrayl grouphaving 1-20 carbon atoms, or an arylene group having 6-30 carbon atoms,these groups may have hetero atom(s) such as O, S and N, and a part ofthe hydrogen atoms bound to the carbon atom thereof may be substitutedwith a hydroxyl group, a carboxyl group, an acyl group or halogen atoms.Preferably, c5 is an integer of 1 to 3.

Illustrative examples of crosslinking type acetal group shown in thegeneral formula (AL-11a) or (AL-11b) may include those represented bythe following formulae (AL-11)-35 to (AL-11)-42.

Examples of the tertiary alkyl group shown in the formula (AL-12) mayinclude: tert-butyl group, triethylcarbyl group, 1-ethylnorbornyl group,1-methylcyclohexyl group, 1-ethylcyclopentyl group, tert-amyl group, andthe like, or those represented by the following general formulae(AL-12)-1 to (AL-12)-16.

In the formulae, R⁶⁴ may be the same or different, represents a linear,branched or cyclic alkyl group having 1-8 carbon atoms, an aryl grouphaving 6-20 carbon atoms, or an aralkyl group having 7-20 carbon atoms.R⁶⁵ and R⁶⁷ represent a hydrogen atom or a linear, branched or cyclicalkyl group having 1-20 carbon atoms. R⁶⁶ represents an aryl grouphaving 6-20 carbon atoms or an aralkyl group having 7-20 carbon atoms.

Furthermore, as shown in the following formulae (AL-12)-17 and(AL-12)-18, the intramolecular or intermolecular crosslinking may beperformed in the polymer by containing R⁶⁸ which is a bivalent or morealkylene group or an arylene group. In the formulae (AL-12)-17 and(AL-12)-18, R⁶⁴ is the same as explained above, R⁶⁸ represents a linear,branched or cyclic alkylene group having 1-20 carbon atoms or an arylenegroup, and may contain hetero atom(s) such as oxygen, sulfur andnitrogen. b6 is an integer of 1 to 3.

Furthermore, R⁶⁴, R⁶⁵, R⁶⁶ and R⁶⁷ may have the hetero atom(s) such asoxygen, nitrogen, sulfur, and the like, and are specifically representedby the following formulae (AL-13)-1 to (AL-13) -7.

The resist lower layer film composition of the present inventioncomprises as a base the polymer indispensably having the repeating unitof (meth)acrylic ester having the hexafluoroalcohol group or the groupobtained by substituting its hydroxy group with the acid labile group,represented by the general formula (1), and may have a repeating unit bhaving epoxy, oxetanyl, hydroxy, carboxyl and the like for enhancing acrosslinking efficiency. The monomer for obtaining this repeating unit bcan be specifically exemplified as follows.

To make the resist lower layer film composition function as theantireflection film, it is preferable that the polymer comprises therepeating unit having the highly light absorbing aromatic group. Themonomer for obtaining such a highly light absorbing repeating unit c canbe exemplified specifically as follows.

The resist lower layer film composition of the present invention mayfurther have the repeating unit d for enhancing the adhesiveness to theresist and preventing the diffusion and migration of acids and aminefrom the resist. The monomers for obtaining this repeating unit d aremonomers having a hydroxy group, a lactone ring, an ester group, anether group, a cyano group and an acid anhydrate used as adhesive groupsof the resist, and specifically exemplified as follows. Particularly,among the followings, in the case of the repeating unit having7-oxanorbornane as a partial structure, a 7-oxanorbornane ring is openedby acid and heat to crosslink.

Here, the specific structures of the monomers a to d are as the above,and ratios of copolymerization are 0<a≦1.0, 0≦b≦0.8, 0≦c≦0.8, 0≦d≦0.8,0.05≦b+c+d≦0.9, more preferably 0.1≦a≦0.9, 0≦b≦0.7, 0≦c≦0.7, 0≦d≦0.7,0.1≦b+c+d≦0.9, and still more preferably 0.15≦a≦0.8, 0≦b≦0.6, 0≦c≦0.6,0≦d≦0.6, 0.2≦b+c+d≦0.8.

The formula a+b+c+d=1 is preferable, and indicates that a total amountof the repeating units, a, b, c and d is 100 mole % relative to a totalamount of all the repeating units in the polymer (copolymer) containingthe repeating units a, b, c and d.

The monomer for obtaining the repeating unit a represented by thegeneral formula (1) is (meth)acrylic ester having the hexafluoroalcoholgroup or the group obtained by substituting its hydroxy group with theacid labile group. The hydrogen atom in the hydroxy group may have beensubstituted with an acetyl group, a formyl group, a pivaloyl group, anacetal group, a tertiary alkyl group having 4-16 carbon atoms, or atrimethylsilyl group or the like upon polymerization, and deprotectionafter the polymerization may make the hydroxy group.

In one method for synthesizing the copolymer contained in the resistlower layer film composition (antireflection film composition) of thepresent invention, (meth)acrylic ester having the hexafluoroalcoholgroup and an olefin monomer having the light absorbing group arethermally polymerized in the organic solvent by adding a radicalpolymerization initiator or a cationic polymerization initiator. Ahydroxy group in the monomer containing the hydroxy group has beensubstituted with an acetyl group, and then alkali hydrolysis of theresulting polymer compound can also be performed in the organic solventto deprotect the acetyl group. Examples of the organic solvent used inthe polymerization may include: toluene, benzene, tetrahydrofuran,diethyl ether, dioxane and the like. Examples of the radicalpolymerization initiator may include: 2,2′-azobisisobutylonitrile(AIBN), 2,2′-azobis(2,4-dimethylvaleronitrile), dimethyl2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide andthe like. Preferably, the polymerization can be performed by heating at50 to 80° C. Examples of the cationic polymerization initiator mayinclude: acids such as sulfuric acid, phosphoric acid, hydrochloricacid, nitric acid, hypochlorous acid, trichloroacetic acid,trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonicacid, camphor sulfonic acid and tosic acid; Friedel Crafts catalystssuch as BF₃, AlCl₃, TiCl₄ and SnCl₄; and substances that tend to producecations such as I₂ and (C₆H₅)₃CCl.

A reaction time is 2 to 100 hours, and preferably 5 to 20 hours. As abase upon alkali hydrolysis, aqueous ammonia and triethylamine can beused. A reaction temperature is −20 to 100° C. and preferably 0 to 60°C. The reaction time is 0.2 to 100 hours and preferably 0.5 to 20 hours.

A weight average molecular weight of the polymer according to thepresent invention, obtained by gel permeation chromatography (GPC) interms of polystyrene is preferably in the range of 1,500 to 200,000 andmore preferably 2,000 to 100,000. A molecular weight distribution is notparticularly limited, and it is possible to remove low molecularcomponents and high molecular components by fractionation to reduce adispersion degree. Two or more polymers of the general formula (1) whichare different in molecular weight or dispersion degree may be mixed, ortwo or more polymers of the general formula (1) having differentcomposition ratios may be mixed.

The base resin for the resist lower layer film composition of thepresent invention is comprises at least the polymer obtained bypolymerizing (meth)acrylic ester having the hexafluoroalcohol group orthe group obtained by substituting its hydroxy group with the acidlabile group, and can be blended with the polymer shown below. Forexample, to embed a hole without generating voids, the polymer having alow glass transition temperature is used, and the resin is embedded to abottom of the hole with thermal flow at lower temperature than acrosslinking temperature (e.g., see Japanese patent Lapid-open (Kokai)No. 2000-294504-A). An embedding property of a via hole can be enhancedby lowering the glass transition temperature by blending with thepolymer having the low glass transition temperature, particularly theglass transition temperature at 180° C. or below, inter alia, 100 to170° C., e.g., one or two or more copolymers selected from acrylderivatives, vinyl alcohol, vinyl ethers, allyl ethers, styrenederivatives, allyl benzene derivatives, olefins such as ethylene,propylene and butadiene; the polymer obtained by ring-opening metathesispolymerization, novolak resins, dicyclopentadiene resins, phenolicballast compounds, cyclodextrins, steroids such as cholic acid,monosaccharides, polysaccharides, calixarenes and fullerenes.

It is preferable that the resist lower layer film composition furthercontains one or more of an organic solvent, an acid generator and acrosslinking agent.

If the resist lower layer film composition further contains the organicsolvent, an application property of the resist lower layer filmcomposition can be further enhanced. If the resist lower layer filmcomposition further contains one or more of the acid generators and thecrosslinking agents, a crosslinking reaction in the resist lower layerfilm can be facilitated by baking after applying on the substrate.Therefore, a dense film can be obtained, there is little possibility ofintermixing with the resist upper layer film, and there is few diffusionof low molecular components into the resist upper layer film or thelike. As a result, an excellent resist pattern can be obtained, and anexcellent pattern can be formed on the substrate.

As the performance required for the resist lower layer film, it isincluded that there is no intermixing with the resist upper layer filmand no diffusion of the low molecular components to the resist upperlayer film (e.g., see Proc. SPIE, vol. 2195: 225-229, 1994). Toaccomplish these performances, generally the resist lower layer film isformed on the substrate by spin-coating, and then thermally crosslinkedby baking. Therefor, the method of adding the crosslinking agent as thecomponent of the resist lower layer film composition and the method ofintroducing the repeating unit having a crosslinkable substituent intothe polymer are available.

Specific examples of the addition type crosslinking agent which can beused in the present invention may include: a melamine compound, aguanamine compound, a glycol uryl compound or an urea compound eachsubstituted with at least one group selected from a methylol group, analkoxy methyl group and an acyloxy methyl group; an epoxy compound, anisocyanate compound, an azide compound, a compound including a doublebond such as an alkenyl ether group, and the like. These compounds maybe used as an additive, or may be introduced into a polymer side chainas a pendant group. Moreover, a compound containing a hydroxy group mayalso be used as a crosslinking agent.

Examples of the epoxy compound among the above-mentioned specificexamples of the crosslinking agent may include:tris(2,3-epoxypropyl)isocyanurate, trimethylol methanetriglycidyl ether,trimethylol propane triglycidyl ether, triethylol ethanetriglycidylether, and the like. Examples of the melamine compound may include:hexamethylol melamine, hexamethoxy methyl melamine, a compound in which1 to 6 methylol groups of hexamethylol melamine are methoxy methylatedor a mixture thereof, hexamethoxy ethyl melamine, hexaacyloxy methylmelamine, a compound in which 1 to 6 methylol groups of hexamethylolmelamine are acyloxy methylated or a mixture thereof, and the like.Examples of a guanamine compound may include: tetramethylol guanamine,tetra methoxy methyl guanamine, a compound in which 1 to 4 methylolgroups of tetramethylol guanamine are methoxy-methylated and a mixturethereof, tetramethoxy ethyl guanamine, tetraacyloxy guanamine, acompound in which 1 to 4 methylol groups of tetramethylol guanamine areacyloxy-methylated and a mixture thereof, and the like. Examples of aglycol uryl compound may include: tetramethylol glycol uryl,tetramethoxy glycol uryl, tetramethoxy methyl-glycol uryl, a compound inwhich 1-4 methylol groups of tetramethylol glycol uryl are methoxymethylated or a mixture thereof, and a compound in which 1 to 4 methylolgroup of tetramethylol glycol uryl are acyloxy methylated or a mixturethereof, and the like. Examples of a urea compound may include: tetramethylol urea, tetra methoxy methyl urea, a compound in which 1 to 4methylol groups of tetra methylol urea are methoxy-methylated or amixture thereof, tetra methoxy ethyl urea, and the like.

Examples of the isocyanate compound may include: tolylene diisocyanate,diphenyl methane diisocyanate, hexamethylene diisocyanate, cyclohexanediisocyanate, and the like. Examples of the azide compound may include:1,1′-biphenyl-4,4′-bisazide, 4,4′-methylidene bisazide,4,4′-oxy-bisazide, and the like.

Examples of the compound containing an alkenyl ether group may include:ethylene glycol divinyl ether, triethylene-glycol divinyl ether,1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether,tetramethylene-glycol divinyl ether, neo pentyl glycol divinyl ether,trimethylol-propane trivinyl ether, hexane diol divinyl ether,1,4-cyclohexane diol divinyl ether, pentaerythritol trivinyl ether,pentaerythritol tetra vinyl ether, sorbitol tetra vinyl ether, sorbitolpenta vinyl ether, trimethylol-propane trivinyl ether, and the like.

When the hydroxy groups in the polymer contained in the resist lowerlayer film composition of the present invention, e.g., the polymerhaving the repeating unit represented by the general formula (1) havebeen partially substituted with a glycidyl group, the addition of thecompound comprising the hydroxy group(s) is effective. In particular,the compound comprising two or more hydroxy groups in the molecule ispreferable. Examples of the compound containing a hydroxy group orhydroxy groups may include: a compound containing an alcohol group suchas naphthol novolak, m- and p-cresol novolak, naphthol dicyclopentadienenovolak, m- and p-cresol dicyclopentadiene novolak,4,8-bis(hydroxymethyl)tricyclo[5.2.1.0^(2,6)]-decane, pentaerythritol,1,2,6-hexanetriol, 4,4′,4″-methylidene tris cyclohexanol,4,4′-[1-[4-[1-(4-hydroxycyclohexyl)-1-methylethyl]phenyl]ethylidene]biscyclohexanol,[1,1′-bicyclohexyl]-4,4′-diol, methylene biscyclohexanol, decahydronaphthalene-2,6-diol, [1,1′-bicyclohexyl]-3,3′,4,4′-tetrahydroxy and thelike; and phenolic ballast compounds such as bisphenol, methylenebisphenol, 2,2′-methylene bis[4-methyl phenol],4,4′-methylidene-bis[2,6-dimethylphenol],4,4′-(1-methyl-ethylidene)bis[2-methyl phenol], 4,4′-cyclohexylidenebisphenol, 4,4′-(1,3-dimethyl butylidene)bisphenol,4,4′-(1-methyl-ethylidene)bis[2,6-dimethyl phenol], 4,4′-oxybisphenol,4,4′-methylene bisphenol, bis(4-hydroxyphenyl)methanone, 4,4′-methylenebis[2-methylphenol], 4,4′-[1,4-phenylene bis(1-methylethylidene)]bisphenol, 4,4′-(1,2-ethane-di-yl)bisphenol, 4,4′-(diethylsilylene)bisphenol,4,4′-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]bisphenol,4,4′,4″-methylidene trisphenol,4,4′-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol,2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methyl phenol,4,4′,4″-ethylidyne tris[2-methyl phenol], 4,4′,4″-ethylidyne trisphenol,4,6-bis[(4-hydroxy phenyl)methyl]1,3-benzene diol, 4,4′-[(3,4-dihydroxyphenyl)methylene]bis[2-methylphenol],4,4′,4″,4′″-(1,2-ethanediylidene)tetrakisphenol, 2,2′-methylenebis[6-[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenol],4,4′,4″,4′″-(1,4-phenylene dimethylidyne)tetrakisphenol,2,4,6-tris(4-hydroxy phenylmethyl)-1,3-benzenediol, 2,4′,4″-methylidenetrisphenol, 4,4′,4′″-(3-methyl-1-propanyl-3-ylidene)trisphenol,2,6-bis[(4-hydroxy-3-phlorophenyl)methyl]-4-fluorophenol,2,6-bis[4-hydroxy-3-fluorophenyl]methyl]-4-fluorophenol,3,6-bis[(3,5-dimethyl-4-hydroxyphenyl)methyl]1,2-benzenediol,4,6-bis[(3,5-dimethyl-4-hydroxy phenyl)methyl]1,3-benzenediol,p-methylcalix[4]allene, 2,2′-methylenebis[6-[(2,5/3,6-dimethyl-4/2-hydroxyphenyl)methyl]-4-methylphenol,2,2′-methylene bis[6-[(3,5-dimethyl-4-hydroxyphenyl) methyl]-4-methylphenol, 4,4′,4″,4′″-tetrakis[(1-methylethylidene)bis(1,4-cyclohexylidene)]-phenol, 6,6′-methylenebis[4-(4-hydroxy phenyl methyl)-1,2,3-benzentriol,3,3′,5,5′-tetrakis[(5-methyl-2-hydroxyphenyl)methyl]-[(1,1′-biphenyl)-4,4′-diol],and the like.

The amount of the crosslinking agent to be combined in the resist lowerlayer film composition of the present invention is preferably 5 to 50parts (parts by mass, the same applies below) and particularlypreferably 10 to 40 parts based on 100 parts of the base polymer (totalresin content). When the amount is 5 parts or more, there is littlepossibility of mixing with the resist film. When it is 50 parts or less,there is little possibility of reducing the antireflection effect andcausing cracks in the film after crosslinking.

In order to promote crosslinking reactions by heat in the resist lowerlayer film composition according to the present invention, an acidgenerator may be further added. As for acid generators, there are acidgenerators that generate acids upon thermal decomposition and acidgenerators that generates acids upon photoirradiation. Such a photoacidgenerator and/or a thermalacid generator may be added.

Examples of an acid generator that may be added to the resist lowerlayer film composition according to the present invention are asfollows:

-   (i) an onium salt represented by the following general formulae    (P1a-1), (P1a-2), (2) or (P1b),-   (ii) a diazomethane derivative represented by the following general    formula (P2),-   (iii) a glyoxime derivative represented by the following general    formula (P3),-   (iv) a bis sulfone derivative represented by the following general    formula (P4),-   (v) a sulfonate of an N-hydroxy imide compound represented by the    following general formula (P5),-   (vi) a β-keto sulfonic-acid derivative,-   (vii) a disulfone derivative,-   (viii) a nitro benzyl sulfonate derivative, and-   (ix) a sulfonate derivative, and the like.

(In the formulae R^(101a), R^(101b), and R^(101c) independentlyrepresent a linear, branched or cyclic alkyl group, alkenyl group,oxoalkyl group or oxoalkenyl group each having 1-12 carbon atoms, anaryl group having 6-20 carbon atoms, or an aralkyl group or an aryloxoalkyl group having 7-12 carbon atoms. Hydrogen atoms in part or inentirety of these groups may be substituted with an alkoxy group or thelike. R^(101b) and R^(101c) may form a ring. In the case that they forma ring, R^(101b) and R^(101c) represent an alkylene group having 1-6carbon atoms respectively. R^(101d), R^(101e), R^(101f) and R^(101g)each represent a hydrogen atom, a linear, branched or cyclic alkylgroup, alkenyl group, oxoalkyl group or oxoalkenyl group each having1-12 carbon atoms, an aryl group having 6-20 carbon atoms, or an aralkylgroup or an aryloxoalkyl group each having 7-12 carbon atoms where apart of or all of hydrogen atoms may be substituted with an alkoxygroup. R^(101d) and R^(101e), and R^(101d), R^(101e) and R^(101f) canform a ring respectively. When they form a ring, R^(101d) and R^(101e),and R^(101d), R^(101e), and R^(101f), represent an alkylene group having3-10 carbon atoms or a heteroaromatic ring having the nitrogen atom inthe formula in the ring. K⁻ represents a non-nucleophilic counter ion.)

The R^(101a), R^(101b), R^(101c), R^(101d), R^(101e), R^(101f) andR^(101g) may be the same or different mutually. Examples thereof as analkyl group may include: a methyl group, an ethyl group, a propyl group,an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butylgroup, a pentyl group, a hexyl group, a heptyl group, an octyl group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopropyl methyl group, a 4-methyl cyclohexyl group, a cyclohexylmethyl group, a norbornyl group, an adamantyl group, and the like.Examples of an alkenyl group may include: a vinyl group, an allyl group,a propenyl group, a butenyl group, a hexenyl group, a cyclohexenylgroup, and the like. Examples of an oxo alkyl group may include:2-oxocyclopentyl group, 2-oxocyclohexyl group, 2-oxopropyl group,2-cyclopentyl-2-oxoethyl group, 2-cyclohexyl-2-oxoethyl group,2-(4-methylcyclohexyl)-2-oxoethyl group, and the like. Examples of anoxo alkenyl group may include: 2-oxo-4-cyclohexenyl group,2-oxo-4-propenyl group, and the like. Examples of an aryl group mayinclude: a phenyl group, a naphthyl group, and the like; an alkoxyphenyl group such as p-methoxyphenyl group, m-methoxyphenyl group,o-methoxyphenyl group, an ethoxyphenyl group, p-tert-butoxyphenyl groupor m-tert-butoxy phenyl group; an alkyl phenyl group such as2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, anethylphenyl group, 4-tert-butylphenyl group, 4-butylphenyl group, or adimethyl phenyl group; an alkyl naphthyl group such as a methylnaphthylgroup or an ethyl naphthyl group; an alkoxy naphthyl group such as amethoxy naphthyl group or an ethoxy naphthyl group; a dialkyl naphthylgroup such as a dimethyl naphthyl group or a diethyl naphthyl group; adialkoxy naphthyl group such as a dimethoxy naphthyl group or a diethoxynaphthyl group. Examples of an aralkyl group may include a benzyl group,a phenylethyl group, a phenethyl group, and the like. Examples of anaryl oxoalkyl group may include: 2-aryl-2-oxoethyl group such as2-phenyl-2-oxoethyl group, 2-(1-naphthyl)-2-oxoethyl group,2-(2-naphthyl)-2-oxoethyl group, and the like.

Examples of a non-nucleophilic counter ion as K⁻ may include: a halideion such as a chloride ion or a bromide ion; a fluoro alkyl sulfonatesuch as triflate, 1,1,1-trifluoro ethanesulfonate, or nonafluoro butanesulfonate; an aryl sulfonate such as tosylate, benzene sulfonate,4-fluorobenzene sulfonate, or 1,2,3,4,5-pentafluoro benzene sulfonate;and an alkyl sulfonate such as mesylate or butane sulfonate; imidic acidsuch as bis(trifluoromethyl sulfonyl)imide, bis(perfluoroethylsulfonyl)imide, or bis(perfluorobutyl sulfonyl)imide; methide acid suchas tris(trifluoromethyl sulfonyl)methide, or tris(perfluoroethylsulfonyl)methide; sulfonates represented by the following generalformula (K-1) which are substituted with fluorine atoms at α position;and sulfonates represented by the following general formula (K-2) whichare substituted with fluorine atoms at α and β positions.

In the general formula (K-1), R¹⁰² represents a hydrogen atom, a linear,branched or cyclic alkyl group, acyl group each having 1-20 carbonatoms, an alkenyl group having 2-20 carbon atoms, an aryl group having6-20 carbon atoms, or an aryloxy group.

In the general formula (K-2), R¹⁰³ represents a hydrogen atom, a linear,branched or cyclic alkyl group having 1-20 carbon atoms, an alkenylgroup having 2-20 carbon atoms, or an aryl group having 6-20 carbonatoms.

As a non-nucleophilic counter ion represented by K⁻, a sulfonatesubstituted with fluorine at α position may be used most preferablybecause its acid strength is strong and its crosslinking reaction rateis fast.

In addition, examples of a heteroaromatic ring in which R^(101d),R^(101e), R^(101f) and R^(101g) have the nitrogen atom in the formula inthe ring may include: an imidazole derivative (for example, imidazole,4-methyl imidazole, 4-methyl-2-phenyl imidazole, or the like), apyrazole derivative, a furazan derivative, a pyrroline derivative (forexample, pyrroline, 2-methyl-1-pyrroline, or the like), a pyrrolidinederivative (for example, pyrrolidine, N-methyl pyrrolidine,pyrrolidinone, N-methyl pyrolidone, or the like), an imidazolinederivative, an imidazolidine derivative, a pyridine derivative (forexample, pyridine, methyl pyridine, ethyl pyridine, propyl pyridine,butyl pyridine, 4-(1-butyl pentyl)pyridine, dimethyl pyridine, trimethylpyridine, triethyl pyridine, phenyl pyridine, 3-methyl-2-phenylpyridine, 4-tert-butyl pyridine, diphenyl pyridine, benzyl pyridine,methoxy pyridine, butoxy pyridine, dimethoxy pyridine,1-methyl-2-pyridone, 4-pyrrolidino pyridine, 1-methyl-4-phenyl pyridine,2-(1-ethylpropyl)pyridine, amino pyridine, dimethyl amino pyridine, orthe like), a pyridazine derivative, a pyrimidine derivative, a pyrazinederivative, a pyrazoline derivative, a pyrazolidine derivative, apiperidine derivative, a piperazine derivative, a morpholine derivative,an indole derivative, an isoindole derivative, a 1H-indazole derivative,an indoline derivative, a quinoline derivative (for example, quinoline,3-quinoline carbonitrile, or the like), an isoquinoline derivative, acinnoline derivative, a quinazoline derivative, a quinoxalinederivative, a phthalazine derivative, a purine derivative, a pteridinederivative, a carbazole derivative, a phenanthridine derivative, anacridine derivative, a phenazine derivative, 1,10-phenanthrolinederivative, an adenine derivative, an adenosine derivative, a guaninederivative, a guanosine derivative, an uracil derivative, an uridinederivative, and the like.

Although (P1a-1) and (P1a-2) have both effects of a photo acid generatorand a thermal acid generator, (2) acts as a thermal acid generator.

(In the formula, R^(102a), and R^(102b) each represents a linear,branched or cyclic alkyl group having 1-8 carbon atoms. R¹⁰³ representsa linear, branched or cyclic alkylene group having 1-10 carbon atoms.R^(104a) and R^(104b) each represents a 2-oxoalkyl group having 3-7carbon atoms. K⁻ represents a non-nucleophilic counter ion.)

Examples of the alkyl group of R^(102a) and R^(102b) may include: amethyl group, an ethyl group, a propyl group, an isopropyl group, an-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, ahexyl group, a heptyl group, an octyl group, a cyclopentyl group, acyclohexyl group, a cyclopropylmethyl group, 4-methylcyclohexyl group, acyclohexyl methyl group, and the like.

Examples of the alkylene group of R¹⁰³ may include: a methylene group,an ethylene group, a propylene group, a butylene group, a pentylenegroup, a hexylene group, a heptylene group, an octylene group, anonylene group, 1,4-cyclohexylene group, 1,2-cyclohexylene group,1,3-cyclopentylene group, 1,4-cyclooctylene group, 1,4-cyclohexanedimethylene group, and the like.

Examples of the 2-oxoalkyl group of R^(104a) and R^(104b) may include:2-oxopropyl group, 2-oxocyclopentyl group, 2-oxocyclohexyl group,2-oxocycloheptyl group, and the like. Examples of K⁻ may include thesame as mentioned in the formulae (P1a-1), (P1a-2) and (2).

Among the onium salts of (P1a-1), (P1a-2), (2) or (P1b), the compoundsrepresented by (P1a-1), (P1a-2) and (P1b) generate acids by light orheat, and the compound represented by (2) generates an acid by heat.Among the onium salts of (P1a-1), (P1a-2), (2) or (P1b), the onium saltof (2) may be used most preferably as the acid generator contained inthe resist lower layer film composition of the present invention. Theammonium salt represented by (2) generates the acid and amine by thermaldecomposition. Thus they are evaporated by heat, and there is littlepossibility of becoming a source of particle formation. Therefore, thereis little possibility of contaminating the substrate upon forming thepattern, and the substrate with high cleanliness can be obtained.

(In the formula, R¹⁰⁵ and R¹⁰⁶ independently represent a linear,branched or cyclic alkyl group or an alkyl halide group each having 1-12carbon atoms, an aryl group or an aryl halide group each having 6-20carbon atoms, or an aralkyl group having 7-12 carbon atoms.)

Examples of an alkyl group as R¹⁰⁵ and R¹⁰⁶ may include: a methyl group,an ethyl group, a propyl group, an isopropyl group, a n-butyl group, asec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, aheptyl group, an octyl group, an amyl group, a cyclopentyl group, acyclohexyl group, a cycloheptyl group, a norbornyl group, an adamantylgroup, and the like.

Examples of an alkyl halide group as R¹⁰⁵ and R¹⁰⁶ may include:trifluoromethyl group, 1,1,1-trifluoroethyl group, 1,1,1-trichloroethylgroup, nonafluoro butyl group, and the like.

Examples of an aryl group may include: a phenyl group, an alkoxyphenylgroup such as p-methoxyphenyl group, m-methoxyphenyl group,o-methoxyphenyl group, an ethoxyphenyl group, p-tert-butoxyphenyl group,or m-tert-butoxyphenyl group; and an alkylphenyl group such as2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, anethylphenyl group, 4-tert-butylphenyl group, 4-butylphenyl group, or adimethylphenyl group.

Examples of an aryl halide group as R¹⁰⁵ and R¹⁰⁶ may include: afluorophenyl group, a chlorophenyl group, 1,2,3,4,5-pentafluoro phenylgroup, and the like.

Examples of an aralkyl group as R¹⁰⁵ and R¹⁰⁶ may include: a benzylgroup, a phenethyl group, and the like.

(In the formula, R¹⁰⁷, R¹⁰⁸ and R¹⁰⁹ independently represent a linear,branched, cyclic alkyl group or an alkyl halide group each having 1-12carbon atoms, an aryl group or an aryl halide group each having 6-20carbon atoms, or an aralkyl group having 7-12 carbon atoms. R¹⁰⁸ andR¹⁰⁹ may be bonded to each other and form a cyclic structure. When theyform a cyclic structure, R¹⁰⁸ and R¹⁰⁹ each independently represents alinear or branched alkylene group having 1-6 carbon atoms. R¹⁰⁵ is thesame as R¹⁰⁵ in the formula (P2).)

Examples of the alkyl group, the alkyl halide group, the aryl group, thearyl halide group, and the aralkyl group as R¹⁰⁷, R¹⁰⁸ and R¹⁰⁹ may bethe same as those explained for R¹⁰⁵ and R¹⁰⁶. Examples of an alkylenegroup for R¹⁰⁸ and R¹⁰⁹ may include: a methylene group, an ethylenegroup, a propylene group, a butylene group, a hexylene group, and thelike.

(In the formula, R^(101a) and R^(101b) are the same as explained above.)

(In the formula, R¹¹⁰ represents an arylene group having 6-10 carbonatoms, an alkylene group having 1-6 carbon atoms or an alkenylene grouphaving 2-6 carbon atoms. Hydrogen atoms in part or in entirety of thesegroups may be further substituted with a linear or branched alkyl groupor an alkoxy group each having 1-4 carbon atoms, a nitro group, anacetyl group, or a phenyl group. R¹¹¹ represents a linear, branched orsubstituted alkyl group, alkenyl group or alkoxy alkyl group each having1-8 carbon atoms, a phenyl group or a naphthyl group. Hydrogen atoms inpart or in entirety of these groups may be substituted with an alkylgroup or an alkoxy group each having 1-4 carbon atoms; a phenyl groupwhich may be substituted with an alkyl group or an alkoxy group eachhaving 1-4 carbon atoms, a nitro group or an acetyl group; a heteroaromatic group having 3-5 carbon atoms; or a chlorine atom or a fluorineatom.)

Examples of the arylene group as R¹¹⁰ may include: 1,2-phenylene group,1,8-naphtylene group, and the like. Examples of the alkylene group mayinclude: a methylene group, an ethylene group, a trimethylene group, atetramethylene group, a phenylethylene group, a norbornane-2,3-di-ylgroup, and the like. Examples of the alkenylene group may include:1,2-vinylene group, 1-phenyl-1,2-vinylene group, 5-norbornene-2,3-di-ylgroup, and the like.

Examples of the alkyl group as R¹¹¹ may be the same as those forR^(101a)-R^(101c). Examples of the alkenyl group as R¹¹¹ may include: avinyl group, a 1-propenyl group, an allyl group, a 1-butenyl group, a3-butenyl group, an isoprenyl group, a 1-pentenyl group, a 3-pentenylgroup, a 4-pentenyl group, a dimethyl allyl group, a 1-hexenyl group, a3-hexenyl group, a 5-hexenyl group, a 1-heptenyl group, a 3-heptenylgroup, a 6-heptenyl group, a 7-octenyl group, and the like. Examples ofthe alkoxy alkyl group may include: a methoxy methyl group, an ethoxymethyl group, a propoxy methyl group, a butoxy methyl group, a pentyloxymethyl group, a hexyloxy methyl group, a heptyloxy methyl group, amethoxy ethyl group, an ethoxy ethyl group, a propoxy ethyl group, abutoxy ethyl group, a pentyloxy ethyl group, a hexyloxy ethyl group, amethoxy propyl group, an ethoxy propyl group, a propoxy propyl group, abutoxy propyl group, a methoxy butyl group, an ethoxy butyl group, apropoxy butyl group, a methoxy pentyl group, an ethoxy pentyl group, amethoxy hexyl group, a methoxy heptyl group, and the like.

Examples of the alkyl group having 1-4 carbon atoms which may be furthersubstituted may include: a methyl group, an ethyl group, a propyl group,an isopropyl group, a n-butyl group, an isobutyl group, a tert-butylgroup, and the like. Examples of the alkoxy group having 1-4 carbonatoms may include: a methoxy group, an ethoxy group, a propoxy group, anisopropoxy group, a n-butoxy group, an isobutoxy group, a tert-butoxygroup, and the like.

Examples of the phenyl group which may be substituted with an alkylgroup, an alkoxy group each having 1-4 carbon atoms, a nitro group or anacetyl group may include: a phenyl group, a tolyl group, a p-tert-butoxyphenyl group, a p-acetyl phenyl group, a p-nitrophenyl group, and thelike. Examples of a hetero aromatic group having 3-5 carbon atoms mayinclude: a pyridyl group, a furyl group, and the like.

Examples of the acid generator may include: an onium salt such astetramethyl ammonium trifluoromethane sulfonate, tetramethyl ammoniumnonafluoro butane sulfonate, triethyl ammonium nonafluoro butanesulfonate, pyridinium nonafluoro butane sulfonate, triethyl ammoniumcamphor sulfonate, pyridinium camphor sulfonate, tetra n-butyl-ammoniumnonafluoro butane sulfonate, tetraphenyl ammonium nonafluoro butanesulfonate, tetramethyl ammonium p-toluene sulfonate, diphenyl iodiniumtrifluoromethane sulfonate, (p-tert-butoxy phenyl)phenyl iodiniumtrifluoromethane sulfonate, diphenyl iodinium p-toluene sulfonate,(p-tert-butoxy phenyl)phenyl iodinium p-toluene sulfonate, triphenylsulfonium trifluoromethane sulfonate, (p-tert-butoxy phenyl)diphenylsulfonium trifluoromethane sulfonate, bis(p-tert-butoxy phenyl)phenylsulfonium trifluoromethane sulfonate, tris(p-tert-butoxyphenyl)sulfonium trifluoromethane sulfonate, triphenyl sulfoniump-toluene sulfonate, (p-tert-butoxy phenyl)diphenyl sulfonium p-toluenesulfonate, bis(p-tert-butoxy phenyl)phenyl sulfonium p-toluenesulfonate, tris(p-tert-butoxy phenyl)sulfonium p-toluene sulfonate,triphenyl sulfonium nonafluoro butane sulfonate, triphenyl sulfoniumbutane sulfonate, trimethyl sulfonium trifluoromethane sulfonate,trimethyl sulfonium p-toluene sulfonate, cyclohexylmethyl(2-oxocyclohexyl)sulfonium trifluoromethane sulfonate, cyclohexylmethyl(2-oxo cyclohexyl)sulfonium p-toluene sulfonate, dimethyl phenylsulfonium trifluoromethane sulfonate, dimethyl phenyl sulfoniump-toluene sulfonate, dicyclohexyl phenyl sulfonium trifluoromethanesulfonate, dicyclohexyl phenyl sulfonium p-toluene sulfonate,trinaphthylsulfonium trifluoromethane sulfonate,(2-norbonyl)methyl(2-oxocyclohexyl)sulfonium trifluoromethane sulfonate,ethylene bis[methyl(2-oxocyclopentyl)sulfonium trifluoromethanesulfonate], 1,2′-naphthyl carbonyl methyl-tetrahydro thiopheniumtriflate, triethyl ammonium nonaflate, tributyl ammonium nonaflate,tetraethyl ammonium nonaflate, tetrabutyl ammonium nonaflate, triethylammonium bis(trifluoromethylsulfonyl)imide, triethyl ammoniumtris(perfluoroethylsulfonyl)methide, and the like.

Examples of a diazomethane derivative may include: bis(benzenesulfonyl)diazomethane, bis(p-toluene sulfonyl)diazomethane, bis(xylenesulfonyl)diazomethane, bis(cyclohexyl sulfonyl)diazomethane,bis(cyclopentyl sulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane,bis(isobutyl sulfonyl)diazomethane, bis(sec-butylsulfonyl)diazomethane,bis(n-propylsulfonyl)diazomethane, bis(isopropyl sulfonyl)diazomethane,bis(tert-butyl-sulfonyl)diazomethane, bis(n-amylsulfonyl)diazomethane,bis(isoamylsulfonyl)diazomethane, bis(sec-amylsulfonyl)diazomethane,bis(tert-amylsulfonyl)diazomethane,1-cyclohexylsulfonyl-1-(tert-butyl-sulfonyl)diazomethane, 1-cyclohexylsulfonyl-1-(tert-amyl sulfonyl)diazomethane, 1-tert-amylsulfonyl-1-(tert-butyl-sulfonyl)diazomethane, and the like.

Examples of a glyoxime derivative may include: bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime, bis-O-(p-toluene sulfonyl)-α-diphenylglyoxime, bis-O-(p-toluene sulfonyl)-α-dicyclohexyl glyoxime,bis-O-(p-toluene sulfonyl)-2,3-pentanedione glyoxime, bis-O-(p-toluenesulfonyl)-2-methyl-3,4-pentanedione glyoxime, bis-O-(n-butanesulfonyl)-α-dimethylglyoxime, bis-O-(n-butane sulfonyl)-α-diphenylglyoxime, bis-O-(n-butane sulfonyl)-α-dicyclohexyl glyoxime,bis-O-(n-butane sulfonyl)-2,3-pentanedione glyoxime, bis-O-(n-butanesulfonyl)-2-methyl-3,4-pentanedione glyoxime, bis-O-(methanesulfonyl)-α-dimethylglyoxime, bis-O-(trifluoromethanesulfonyl)-α-dimethylglyoxime, bis-O-(1,1,1-trifluoro ethanesulfonyl)-α-dimethylglyoxime, bis-O-(tert-butanesulfonyl)-α-dimethylglyoxime, bis-O-(perfluoro octanesulfonyl)-α-dimethylglyoxime, bis-O-(cyclohexanesulfonyl)-α-dimethylglyoxime, bis-O-(benzenesulfonyl)-α-dimethylglyoxime, bis-O-(p-fluorobenzenesulfonyl)-α-dimethylglyoxime, bis-O-(p-tert-butylbenzenesulfonyl)-α-dimethylglyoxime, bis-O-(xylenesulfonyl)-α-dimethylglyoxime, bis-O-(camphorsulfonyl)-α-dimethylglyoxime, and the like.

Examples of a bissulfone derivative may include: bis naphthyl sulfonylmethane, bis-trifluoro methyl sulfonyl methane, bis methyl sulfonylmethane, bis ethyl sulfonyl methane, bis propyl sulfonyl methane, bisisopropyl sulfonyl methane, bis-p-toluene sulfonyl methane, bis benzenesulfonyl methane, and the like.

Examples of the β-ketosulfone derivative may include: 2-cyclohexylcarbonyl-2-(p-toluene sulfonyl) propane, 2-isopropylcarbonyl-2-(p-toluene sulfonyl) propane, and the like.

Examples of the disulfone derivative may include: a diphenyl disulfonederivative, a dicyclohexyl disulfone derivative, and the like.

Examples of the nitro benzyl sulfonate derivative may include:2,6-dinitro benzyl p-toluenesulfonate, 2,4-dinitro benzylp-toluenesulfonate, and the like.

Examples of the sulfonate derivative may include: 1,2,3-tris(methanesulfonyloxy)benzene, 1,2,3-tris(trifluoromethane sulfonyloxy)benzene,1,2,3-tris(p-toluene sulfonyloxy)benzene, and the like.

Examples of the sulfonate derivative of N-hydroxy imide compound mayinclude: N-hydroxy succinimide methane sulfonate, N-hydroxy succinimidetrifluoromethane sulfonate, N-hydroxy succinimide ethane sulfonate,N-hydroxy succinimide 1-propane sulfonate, N-hydroxy succinimide2-propane sulfonate, N-hydroxy succinimide 1-pentane sulfonate,N-hydroxy succinimide 1-octane sulfonate, N-hydroxy succinimidep-toluenesulfonate, N-hydroxy succinimide p-methoxybenzene sulfonate,N-hydroxy succinimide 2-chloroethane sulfonate, N-hydroxy succinimidebenzenesulfonate, N-hydroxy succinimide-2,4,6-trimethyl benzenesulfonate, N-hydroxy succinimide 1-naphthalene sulfonate, N-hydroxysuccinimide 2-naphthalene sulfonate, N-hydroxy-2-phenyl succinimidemethane sulfonate, N-hydroxy maleimide methane sulfonate, N-hydroxymaleimide ethane sulfonate, N-hydroxy-2-phenyl maleimide methanesulfonate, N-hydroxy glutarimide methane sulfonate, N-hydroxyglutarimide benzenesulfonate, N-hydroxy phthalimide methane sulfonate,N-hydroxy phthalimide benzenesulfonate, N-hydroxy phthalimidetrifluoromethane sulfonate, N-hydroxy phthalimide p-toluenesulfonate,N-hydroxy naphthalimide methane sulfonate, N-hydroxy naphthalimidebenzenesulfonate, N-hydroxy-5-norbornene-2,3-dicarboxyimide methanesulfonate, N-hydroxy-5-norbornene-2,3-dicarboxyimide trifluoromethanesulfonate, N-hydroxy-5-norbornene-2,3-dicarboxyimide p-toluenesulfonate,and the like.

In particular, preferred examples of acid generators may include: anonium salt such as triphenyl sulfonium trifluoromethane sulfonate,(p-tert-butoxy phenyl)diphenyl sulfonium trifluoromethane sulfonate,tris(p-tert-butoxy phenyl)sulfonium trifluoromethane sulfonate,triphenyl sulfonium p-toluene sulfonate, (p-tert-butoxy phenyl)diphenylsulfonium p-toluene sulfonate, tris(p-tert-butoxy phenyl)sulfoniump-toluene sulfonate, trinaphthylsulfonium trifluoromethane sulfonate,cyclohexyl methyl(2-oxocyclohexyl)sulfonium trifluoromethane sulfonate,(2-norbonyl)methyl(2-oxocyclohexyl)sulfonium trifluoromethane sulfonate,1,2′-naphthyl carbonylmethyl tetrahydrothiophenium triflate, and thelike;

a diazomethane derivative such as bis(benzene sulfonyl)diazomethane,bis(p-toluene sulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane, bis(isobutylsulfonyl)diazomethane, bis(sec-butylsulfonyl)diazomethane, bis(n-propylsulfonyl)diazomethane, bis(isopropyl sulfonyl)diazomethane,bis(tert-butylsulfonyl)diazomethane, and the like;

a glyoxime derivative, such as bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime, bis-O-(n-butanesulfonyl)-α-dimethylglyoxime, and the like;

a bissulfone derivative, such as bisnaphthyl sulfonyl methane;

a sulfonate derivative of N-hydroxyimide compounds, such as N-hydroxysuccinimide methane sulfonate, N-hydroxy succinimide trifluoromethanesulfonate, N-hydroxy succinimide 1-propane sulfonate, N-hydroxysuccinimide 2-propane sulfonate, N-hydroxy succinimide 1-pentanesulfonate, N-hydroxy succininide p-toluene sulfonate, N-hydroxynaphthalimide methane sulfonate, N-hydroxy naphthalimidebenzenesulfonate, and the like.

It should be noted that the acid generators mentioned above may be usedalone or in admixture.

The amount of the acid generator to be added is preferably 0.1 to 50parts, more preferably 0.5 to 40 parts to 100 parts of the base polymer.When the amount is 0.1 parts or more, there is less possibility that anamount of an acid generated is insufficient and sufficient crosslinkingreactions do not occur. When the amount is 50 parts or less, there isless possibility that a mixing phenomenon occurs due to mingration ofacids to an overlying resist.

Furthermore, a basic compound for improving storage stability may befurther added to the resist lower layer film composition according tothe present invention. The basic compound functions as a quencher thatprevents an acid generated in small amounts during storage or the likefrom inducing crosslinking reactions.

Examples of such a basic compound may include: primary, secondary andtertiary aliphatic amines, mixed amines, aromatic amines, heterocyclicamines, nitrogen-containing qcompounds having a carboxy group,nitrogen-containing compounds having a sulfonyl group,nitrogen-containing compounds having a hydroxyl group,nitrogen-containing compounds having a hydroxy phenyl group,nitrogen-containing alcohol compounds, amide derivatives, imidederivatives and the like.

Examples of the primary aliphatic amines may include: ammonia,methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine,isobutyl amine, sec-butyl-amine, tert-butylamine, pentylamine,tert-amylamine, cyclopentyl amine, hexylamine, cyclohexyl amine,heptylamine, octylamine, nonylamine, decyl amine, dodecylamine,cetylamine, methylene diamine, ethylenediamine, tetraethylene pentamineand the like. Examples of the secondary aliphatic amines may include:dimethylamine, diethylamine, di-n-propylamine, diisopropyl amine,di-n-butylamine, diisobutyl amine, di-sec-butylamine, dipentylamine,dicyclopentyl amine, dihexyl amine, dicyclohexyl amine, diheptylamine,dioctylamine, dinonylamine, didecylamine, didodecylamine, dicetylamine,N,N-dimethyl methylenediamine, N,N-dimethyl ethylenediamine,N,N-dimethyl tetraethylene pentamine and the like. Examples of thetertiary aliphatic amines may include: trimethylamine, triethylamine,tri-n-propylamine, triisopropyl amine, tri-n-butyl amine, triisobutylamine, tri-sec-butyl amine, tripentyl amine, tricyclopentyl amine,trihexyl amine, tricyclohexyl amine, triheptyl amine, trioctyl amine,trinonyl amine, tridecyl amine, tridodecyl amine, tricetyl amine,N,N,N′,N′-tetra methyl methylene diamine, N,N,N′,N′-tetramethylethylenediamine, N,N,N′,N′-tetramethyl tetraethylene pentamine and thelike.

Moreover, examples of the mixed amines may include: a dimethylethylamine, methyl ethyl propyl amine, benzylamine, phenethyl amine,benzyl dimethylamine, and the like.

Examples of the aromatic amines and the heterocyclic amines may include:an aniline derivative (for example, aniline, N-methyl aniline, N-ethylaniline, N-propyl aniline, N,N-dimethylaniline, 2-methyl aniline,3-methyl aniline, 4-methyl aniline, ethyl aniline, propyl aniline,trimethyl aniline, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline,2,4-dinitro aniline, 2,6-dinitro aniline, 3,5-dinitro aniline,N,N-dimethyl toluidine, and the like), diphenyl(p-tolyl)amine, methyldiphenylamine, triphenylamine, phenylenediamine, naphthylamine, diaminonaphthalene, a pyrrole derivative (for example, pyrrole, 2H-pyrrole,1-methyl pyrrole, 2,4-dimethyl pyrrole, 2,5-dimethyl pyrrole, N-methylpyrrole, and the like), an oxazole derivative (for example, oxazole,isoxazole and the like), a thiazole derivative (for example, thiazole,isothiazole, and the like), an imidazole derivative (for example,imidazole, 4-methyl imidazole, 4-methyl-2-phenyl imidazole and thelike), a pyrazole derivative, a furazan derivative, a pyrrolinederivative (for example, pyrroline, 2-methyl-1-pyrroline and the like),a pyrrolidine derivative (for example, pyrrolidine, N-methylpyrrolidine, pyrrolidinone, N-methyl pyrolidone and the like), animidazoline derivative, an imidazolidine derivative, a pyridinederivative (for example, pyridine, methyl pyridine, ethyl pyridine,propyl pyridine, butyl pyridine, 4-(1-butyl pentyl)pyridine, dimethylpyridine, trimethyl pyridine, triethyl pyridine, phenyl pyridine,3-methyl-2-phenyl pyridine, 4-tert-butyl pyridine, diphenyl pyridine,benzyl pyridine, methoxy pyridine, butoxy pyridine, dimethoxy pyridine,1-methyl-2-pyridine, 4-pyrrolidino pyridine, 1-methyl-4-phenylpyridine,2-(1-ethylpropyl)pyridine, amino pyridine, dimethyl amino pyridine andthe like), a pyridazine derivative, a pyrimidine derivative, a pyrazinederivative, a pyrazoline derivative, a pyrazolidine derivative, apiperidine derivative, a piperazine derivative, a morpholine derivative,an indole derivative, an isoindole derivative, a 1H-indazole derivative,an indoline derivative, a quinoline derivative (for example, quinoline,3-quinoline carbonitrile, and the like), an isoquinoline derivative, acinnoline derivative, a quinazoline derivative, a quinoxalinederivative, a phthalazine derivative, a purine derivative, a pteridinederivative, a carbazole derivative, a phenanthridine derivative, anacridine derivative, a phenazine derivative, 1,10-phenanthrolinederivative, an adenine derivative, an adenosine derivative, a guaninederivative, a guanosine derivative, an uracil derivative, an uridinederivative and the like.

Furthermore, examples of the nitrogen-containing compounds having acarboxy group may include: aminobenzoic acid, indole carboxylic acid,and an amino acid derivative (for example, nicotinic acid, alanine,arginine, aspartic acid, glutamic acid, glycine, histidine, isoleucine,glycyl leucine, leucine, methionine, phenylalanine, threonine, lysine,3-aminopyrazine-2-carboxylic acid, or methoxy alanine) and the like.Examples of the nitrogen-containing compounds having a sulfonyl groupmay include: 3-pyridine sulfonic acid, pyridinium p-toluene sulfonateand the like. Examples of the nitrogen-containing compounds having ahydroxyl group, the nitrogen-containing compounds having a hydroxyphenyl group, and the nitrogen-containing alcohol compounds may include:2-hydroxy, pyridine, amino cresol, 2,4-quinoline diol, 3-indole methanolhydrate, monoethanolamine, diethanolamine, triethanolamine, N-ethyldiethanolamine, N,N-diethyl ethanolamine, triisopropanol amine,2,2′-iminodiethanol, 2-amino ethanol, 3-amino-1-propanol,4-amino-1-butanol, 4-(2-hydroxyethyl)morpholine,2-(2-hydroxyethyl)pyridine, 1-(2-hydroxyethyl)piperazine,1-(2-(2-hydroxyethoxy)ethyl]piperazine, piperidine ethanol, 1-(2-hydroxyethyl)pyrrolidine, 1-(2-hydroxyethyl)-2-pyrrolidinone,3-piperidino-1,2-propanediol, 3-pyrrolidino-1,2-propanediol, 8-hydroxyjulolidine, 3-quinuclidinol, 3-tropanol, 1-methyl-2-pyrrolidine ethanol,1-aziridine ethanol, N-(2-hydroxyethyl)phthalimide,N-(2-hydroxyethyl)isonicotinamide, and the like.

Examples of the amide derivatives may include: formamide, N-methylformamide, N,N-dimethylfor amide, acetamide, N-methyl acetamide,N,N-dimethylacetamide, propione amide, benzamide, and the like.

Examples of the imide derivatives may include: phthalimide, succininide,maleimide, and the like.

The amount of addition of the basic compound is preferably 0.001 to 2parts, and in particular, 0.01 to 1 part to 100 parts of all the basepolymers. When the amount is 0.001 parts or more, sufficient effects ofadding the compound are obtained. When the amount is 2 parts or less,there is less possibility that the compound traps all acids generated byheat and thus no crosslinking reactions occur.

As the organic solvent that may be added to the resist lower layer filmcomposition according to the present invention, any organic solvent thatdissolves the base polymer, an acid generator, a crosslinker and otheradditives may be used. Examples of such an organic solvent may include:ketones such as cyclohexanone, methyl-2-amyl ketone; alcohols such as3-methoxy butanol, 3-methyl-3-methoxy butanol, 1-methoxy-2-propanol,1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether,ethylene glycol monomethyl ether, propylene glycol monoethyl ether,ethylene glycol monoethyl ether, propylene glycol dimethyl ether, ordiethylene glycol dimethyl ether; and esters such as propylene glycolmonomethyl ether acetate, propylene glycol monoethyl ether acetate,ethyl lactate, ethyl pyruvate, butyl acetate, methyl3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate,tert-butyl propionate, propylene glycol mono methyl ether acetate, orpropylene glycol mono tert-butyl ether acetate. Above solvents may beused alone or in admixture. However, the organic solvent that may beadded to the resist lower layer film composition according to thepresent invention is not restricted to the above solvents. In theantireflection film composition according to the present invention,among the organic solvents, diethylene glycol dimethyl ether,1-ethoxy-2-propanol, ethyl lactate, propylene glycol monomethyl etheracetate, or a mixture thereof are preferably used.

The amount of the organic solvent to be added is preferably 200 to10,000 parts, and more preferably 300 to 5,000 parts to 100 parts of allthe base polymers.

The present invention provides the patterning process for patterning asubstrate with lithography, wherein at least, a resist lower layer filmis formed on the substrate using the resist lower layer filmcomposition, a photoresist film is formed on the resist lower layerfilm, a pattern circuit area of the photoresist film is exposed,subsequently developed with the developer to form a resist pattern onthe photoresist film, the resist lower layer film and the substrate areetched using the resist pattern as a mask to form a pattern on thesubstrate.

Furthermore the present invention provides the patterning process forpatterning a substrate with lithography, wherein at least, an organicfilm is formed on the substrate, a silicon-containing film is formed onthe organic film, a resist lower layer film is formed on thesilicon-containing film using the resist lower layer film composition, aphotoresist film is formed on the resist lower layer film, a patterncircuit area of the photoresist film is exposed, subsequently developedwith the developer to form a resist pattern on the photoresist film, theresist lower layer film and the silicon-containing film are etched usingthe resist pattern as the mask, the organic film is etched using thesilicon-containing film on which the pattern has been formed as themask, and the substrate is further etched to form a pattern on thesubstrate.

Si, SiO₂, SiON, SiN, p-Si, α-Si, W, W—Si, Al, Cu and Al—Si which becomethe substrate to be processed, and various low dielectric films andetching stopper films thereof are used for an under layer of the resistlower layer of the present invention, and can be formed into filmshaving the film thickness of typically 10 to 10,000 nm and particularly20 to 5,000 nm.

Also on the substrate to be processed, a hard mask may be placed forprocessing the substrate to be processed, and as the hard mask, SiN,SION, p-Si, p-Si, α-Si, W, W—Si and the like are used when the substrateto be processed is an SiO₂-based insulation film substrate. When thesubstrate to be processed is a gate electrode of p-Si, W—Si or Al—Si,SiO₂, SiN and SiON are used.

In this case, the resist lower layer film can be formed on the hard maskusing the resist lower layer film composition of the present invention.

Also, the organic film may be formed on the substrate to be processed,and the silicon-containing film may be formed on the organic film. Inthis case, the resist lower layer film can be formed on thesilicon-containing film using the resist lower layer film composition ofthe present invention. Furthermore, the photoresist film can be formedon the resist lower layer film, the pattern circuit area of thephotoresist film is exposed, subsequently developed with the developerto form the resist pattern on the photoresist film, the resist lowerlayer film and the silicon-containing film are etched using the resistpattern as a mask, the organic film is etched using thesilicon-containing film on which the pattern has been formed as a mask,and the substrate can be further etched to form a pattern on thesubstrate.

Subsequently, the method for forming the resist lower layer film of thepresent invention will be described. It is possible to form the resistlower layer film on the substrate by spin-coating method in the same wayas in the ordinary method for forming the photoresist films. Afterforming the resist lower layer film by the spin-coating method, it isdesirable to bake for facilitating the crosslinking reaction in order toevaporate the organic solvent and prevent the mixing with the resistupper layer. A baking temperature is preferably in the range of 80 to300° C. for 10 to 300 seconds. The thickness of the resist lower layerfilm is appropriately selected, and is 10 to 200 nm and particularlypreferably 20 to 150 nm. The film thickness exhibiting the highantireflection effect can be selected when the resist lower layer filmis used as the antireflection film. The resist lower layer film isformed, and subsequently the resist upper layer film is formed thereonin this way.

In this case, the base polymer composed of hydrocarbon known publicly asshown in Japanese patent Lapid-open (Kokai) No. 9-73173-A and Japanesepatent Lapid-open (Kokai) No. 2000-336121-A can be used as a photoresistcomposition for forming this resist upper layer film.

The thickness of the resist upper layer film is not particularlylimited, and is preferably 30 to 500 nm and particularly preferably 50to 400 nm.

When the resist upper layer film is formed using the photoresistcomposition, the spin-coating method is preferably used as is the casewith forming the resist lower layer film. After forming the resist upperlayer film by the spin-coating method, pre-baking is performedpreferably at 80 to 180° C. for 10 to 300 seconds.

Subsequently, according to the standard methods, the pattern circuitarea of the resist film is exposed, and post-exposure baking (PEB) andthe development are performed to give the resist pattern.

A resist overcoat can also be applied onto the upper layer of the resistfilm. The resist overcoat can have the antireflection function, andwater-soluble and water-insoluble materials are available therefor. Asthe water-insoluble material, those soluble in the alkali developer andthose insoluble in the alkali developer and detached by a fluorine basedsolvent are available. The former has a merit in the process in that thedevelopment and the detachment can be performed simultaneously. Whenexposed in liquid immersion, the overcoat is sometimes provided for thepurpose of preventing elution of the additives such as acid generatorsfrom the resist and for the purpose of enhancing a water glidingproperty. As the overcoat, it is preferable to not dissolve in water andto dissolve in the alkali solution, and those obtained by dissolving apolymer compound having α-trifluoromethylhydroxy group in higher alcoholhaving 4 or more carbon atoms or an ether compound having 8-12 carbonatoms are used. The overcoat is formed by spin-coating the solution forthe overcoat on the resist film after the pre-baking, and pre-baking.The thickness of the overcoat is preferably 10 to 200 nm.

When the overcoat is used, after the dry exposure or the exposure inliquid immersion, the post-exposure baking (PEB) is performed, and thedevelopment is performed in the alkali developer for 10 to 300 seconds.As the alkali developer, an aqueous solution of 2.38% by mass oftetramethylammonium hydroxide is generally used widely. When theovercoat soluble in the developer is used, the detachment of theovercoat and the development of the resist film are performedsimultaneously.

When the liquid immersion exposure is performed, in order to completelyremove the water on the overcoat before PEB, it is preferable to dry orcollect the water on the overcoat by spin-dry, purge of surface by dryair or nitrogen before PEB, or by optimizing a water collection nozzleshape or a water collection process on the stage after the exposure. Ifthe water on the protection film is completely removed before PEB, thereis little possibility that a pattern can not be formed because the waterpumps the acid out of the resist during PEB.

In the development, a paddle method or a dip method using the alkaliaqueous solution is used, and in particular, the paddle method using theaqueous solution of 2.38% by mass of tetramethylammonium hydroxide ispreferably used. The resist is developed at room temperature for 10 to300 seconds, then rinsed with purified water and dried by spin-drying ornitrogen-blowing.

Subsequently, the resist lower layer film is etched by dry etching usingthe resist upper layer film on which the resist pattern has been formedas a mask. This etching can be performed by the standard methods. Inertgases such as He and Ar, as well as CO, CO₂, NH₃, SO₂, N₂ and NO₂ gasesin addition to oxygen gas can be added. When the substrate is SiO₂ orSiN, the etching mainly using chlorofluorocarbon gas is performed. Whenthe substrate is polysilicon (p-Si), Al or W, the etching mainly usingchlorine or bromine based gas is performed. The resist lower layer filmof the present invention has a feature that the etching speed is fastupon etching of the substrate.

The pattern is formed on the substrate by this etching.

In the above description, the photoresist composition was shown as thecomposition for forming the resist upper layer film, and the resistlower layer film composition of the present invention can also be usedfor forming the resist lower layer film for preventing the occurrence ofthe footing profile and the undercut of the resist in the case of usingelectron beam exposure other than the case of lithography.

EXAMPLES

The present invention will be specifically described with reference tothe following Examples and Comparative Examples, but the presentinvention is not limited thereto.

Monomers 1 to 6 used in the following Synthesis Examples are shown blow.

Synthesis Example 1

In a 100 mL flask, 8.8 g of monomer 1, 5.7 g of 2,3-epoxypropylmethacrylate ester, 3.1 g of styrene, and 20 g of tetrahydrofuran as asolvent were added. This reaction vessel was cooled to −70° C. undernitrogen atmosphere, and deaeration under reduced pressure and nitrogenflow were repeated three times. 0.1 g of AIBN as a polymerizationinitiator was added after elevating to room temperature, the temperaturewas elevated to 60° C. and reacted for 15 hours. This reaction solutionwas poured in 100 mL of isopropyl alcohol to precipitate. A resultingwhite solid was filtrated, and then dried at 60° C. under reducedpressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 1:2,3-epoxypropyl methacrylate ester:styrene=0.3:0.4:0.3

Molecular weight (Mw)=10,500

Dispersion degree (Mw/Mn)=1.76

This polymer was designated as polymer 1.

Synthesis Example 2

In a 100 mL flask, 8.0 g of monomer 2, 5.7 g of 2,3-epoxypropylmethacrylate ester, 3.1 g of styrene, and 20 g of tetrahydrofuran as asolvent were added. This reaction vessel was cooled to −70° C. undernitrogen atmosphere, and deaeration under reduced pressure and nitrogenflow were repeated three times. 0.1 g of AIBN as a polymerizationinitiator was added after elevating to room temperature, the temperaturewas elevated to 60° C. and reacted for 15 hours. This reaction solutionwas poured in 100 mL of isopropyl alcohol to precipitate. A resultingwhite solid was filtrated, and then dried at 60° C. under reducedpressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 2:2,3-epoxypropyl methacrylate ester:styrene=0.3:0.4:0.3

Molecular weight (Mw)=10,900

Dispersion degree (Mw/Mn)=1.85

This polymer was designated as polymer 2.

Synthesis Example 3

In a 100 mL flask, 7.6 g of monomer 3, 6.4 g of 2,3-dihydroxypropylmethacrylate ester, 3.1 g of styrene, and 20 g of tetrahydrofuran as asolvent were added. This reaction vessel was cooled to −70° C. undernitrogen atmosphere, and deaeration under reduced pressure and nitrogenflow were repeated three times. 0.1 g of AIBN as a polymerizationinitiator was added after elevating to room temperature, the temperaturewas elevated to 60° C. and reacted for 15 hours. This reaction solutionwas poured in 100 mL of isopropyl alcohol to precipitate. A resultingwhite solid was filtrated, and then dried at 60° C. under reducedpressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 3:2,3-dihydroxypropyl methacrylate ester:styrene=0.3:0.4:0.3

Molecular weight (Mw)=8,900

Dispersion degree (Mw/Mn)=1.99

This polymer was designated as polymer 3.

Synthesis Example 4

In a 100 mL flask, 8.8 g of monomer 4, 5.2 g of 2-hydroxyethylmethacrylate ester, 3.1 g of styrene, and 20 g of tetrahydrofuran as asolvent were added. This reaction vessel was cooled to −70° C. undernitrogen atmosphere, and deaeration under reduced pressure and nitrogenflow were repeated three times. 0.1 g of AIBN as a polymerizationinitiator was added after elevating to room temperature, the temperaturewas elevated to 60° C. and reacted for 15 hours. This reaction solutionwas poured in 100 mL of isopropyl alcohol to precipitate. A resultingwhite solid was filtrated, and then dried at 60° C. under reducedpressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 4:2-hydroxyethyl methacrylate ester:styrene=0.3:0.4:0.3

Molecular weight (Mw)=10,600

Dispersion degree (Mw/Mn)=1.88

This polymer was designated as polymer 4.

Synthesis Example 5

In a 100 mL flask, 7.6 g of monomer 2, 7.1 g of α-hydroxymethylacrylate, and 20 g of tetrahydrofuran as a solvent were added. Thisreaction vessel was cooled to −70° C. under nitrogen atmosphere, anddeaeration under reduced pressure and nitrogen flow were repeated threetimes. 0.1 g of AIBN as a polymerization initiator was added afterelevating to room temperature, the temperature was elevated to 60° C.and reacted for 15 hours. This reaction solution was poured in 100 mL ofisopropyl alcohol to precipitate. A resulting white solid was filtrated,and then dried at 60° C. under reduced pressure to yield a whitepolymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 2:α-hydroxymethyl acrylate=0.3:0.7

Molecular weight (Mw)=9,200

Dispersion degree (Mw/Mn)=1.79

This polymer was designated as polymer 5.

Synthesis Example 6

In a 100 mL flask, 8.8 g of monomer 1, 5.7 g of 2,3-epoxypropylmethacrylate ester, 3.6 g of 4-hydroxystyrene, and 20 g oftetrahydrofuran as a solvent were added. This reaction vessel was cooledto −70° C. under nitrogen atmosphere, and deaeration under reducedpressure and nitrogen flow were repeated three times. 0.1 g of AIBN as apolymerization initiator was added after elevating to room temperature,the temperature was elevated to 60° C. and reacted for 15 hours. Thisreaction solution was poured in 100 mL of isopropyl alcohol toprecipitate. A resulting white solid was filtrated, and then dried at60° C. under reduced pressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 1:2,3-epoxypropyl methacrylateester:4-hydroxystyrene=0.3:0.4:0.3

Molecular weight (Mw)=9,900

Dispersion degree (Mw/Mn)=1.82

This polymer was designated as polymer 6.

Synthesis Example 7

In a 100 mL flask, 7.6 g of monomer 2, 5.7 g of 2,3-epoxypropylmethacrylate ester, 4.1 g of phenylvinyl sulfide, and 20 g oftetrahydrofuran as a solvent were added. This reaction vessel was cooledto −70° C. under nitrogen atmosphere, and deaeration under reducedpressure and nitrogen flow were repeated three times. 0.1 g of AIBN as apolymerization initiator was added after elevating to room temperature,the temperature was elevated to 60° C. and reacted for 15 hours. Thisreaction solution was poured in 100 mL of isopropyl alcohol toprecipitate. A resulting white solid was filtrated, and then dried at60° C. under reduced pressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 2:2,3-epoxypropyl methacrylate ester:phenylvinylsulfide=0.3:0.4:0.3

Molecular weight (Mw)=9,500

Dispersion degree (Mw/Mn)=1.88

This polymer was designated as polymer 7.

Synthesis Example 8

In a 100 mL flask, 7.6 g of monomer 2, 5.7 g of 2,3-epoxypropylmethacrylate ester, 5.3 g of benzyl methacrylate, and 20 g oftetrahydrofuran as a solvent were added. This reaction vessel was cooledto −70° C. under nitrogen atmosphere, and deaeration under reducedpressure and nitrogen flow were repeated three times. 0.1 g of AIBN as apolymerization initiator was added after elevating to room temperature,the temperature was elevated to 60° C. and reacted for 15 hours. Thisreaction solution was poured in 100 mL of isopropyl alcohol toprecipitate. A resulting white solid was filtrated, and then dried at60° C. under reduced pressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 2:2,3-epoxypropyl methacrylate ester:benzylmethacrylate=0.3:0.4:0.3

Molecular weight (Mw)=11,000

Dispersion degree (Mw/Mn)=1.89

This polymer was designated as polymer 8.

Synthesis Example 9

In a 100 mL flask, 7.6 g of monomer 2, 5.7 g of 2,3-epoxypropylmethacrylate ester, 8.1 g of 4-hexafluoroisopropylstyrene, and 20 g oftetrahydrofuran as a solvent were added. This reaction vessel was cooledto −70° C. under nitrogen atmosphere, and deaeration under reducedpressure and nitrogen flow were repeated three times. 0.1 g of AIBN as apolymerization initiator was added after elevating to room temperature,the temperature was elevated to 60° C. and reacted for 15 hours. Thisreaction solution was poured in 100 mL of isopropyl alcohol toprecipitate. A resulting white solid was filtrated, and then dried at60° C. under reduced pressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 2:2,3-epoxypropyl methacrylateester:4-hexafluoroisopropylstyrene=0.3:0.4:0.3

Molecular weight (Mw)=8,300

Dispersion degree (Mw/Mn)=1.75

This polymer was designated as polymer 9.

Synthesis Example 10

In a 100 mL flask, 7.6 g of monomer 2, 4.1 g of α-hydroxymethylacrylate, 3.1 g of styrene, and 20 g of tetrahydrofuran as a solventwere added. This reaction vessel was cooled to −70° C. under nitrogenatmosphere, and deaeration under reduced pressure and nitrogen flow wererepeated three times. 0.1 g of AIBN as a polymerization initiator wasadded after elevating to room temperature, the temperature was elevatedto 60° C. and reacted for 15 hours. This reaction solution was poured in100 mL of isopropyl alcohol to precipitate. A resulting white solid wasfiltrated, and then dried at 60° C. under reduced pressure to yield awhite polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 2:α-hydroxymethyl acrylate:styrene=0.3:0.4:0.3

Molecular weight (Mw)=8,900

Dispersion degree (Mw/Mn)=1.71

This polymer was designated as polymer 10.

Synthesis Example 11

In a 100 mL flask, 7.6 g of monomer 2, 4.1 g of α-hydroxymethylacrylate, 5.8 g of benzyl α-hydroxymethylacrylate eater, and 20 g oftetrahydrofuran as a solvent were added. This reaction vessel was cooledto −70° C. under nitrogen atmosphere, and deaeration under reducedpressure and nitrogen flow were repeated three times. 0.1 g of AIBN as apolymerization initiator was added after elevating to room temperature,the temperature was elevated to 60° C. and reacted for 15 hours. Thisreaction solution was poured in 100 mL of isopropyl alcohol toprecipitate. A resulting white solid was filtrated, and then dried at60° C. under reduced pressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 2:α-hydroxymethyl acrylate:benzyl α-hydroxymethyl acrylateeater=0.3:0.4:0.3

Molecular weight (Mw)=9,600

Dispersion degree (Mw/Mn)=1.71

This polymer was designated as polymer 11.

Synthesis Example 12

In a 100 mL flask, 8.0 g of monomer 2, 9.9 g of 2,3-epoxypropylmethacrylate ester, and 20 g of tetrahydrofuran as a solvent were added.This reaction vessel was cooled to −70° C. under nitrogen atmosphere,and deaeration under reduced pressure and nitrogen flow were repeatedthree times. 0.1 g of AIBN as a polymerization initiator was added afterelevating to room temperature, the temperature was elevated to 60° C.and reacted for 15 hours. This reaction solution was poured in 100 mL ofisopropyl alcohol to precipitate. A resulting white solid was filtrated,and then dried at 60° C. under reduced pressure to yield a whitepolymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 2:2,3-epoxypropyl methacrylate ester=0.3:0.7

Molecular weight (Mw)=10,300

Dispersion degree (Mw/Mn)=1.80

This polymer was designated as polymer 12.

Synthesis Example 13

In a 100 mL flask, 9.3 g of monomer 6, 5.7 g of 2,3-epoxypropylmethacrylate ester, 3.1 g of styrene, and 20 g of tetrahydrofuran as asolvent were added. This reaction vessel was cooled to −70° C. undernitrogen atmosphere, and deaeration under reduced pressure and nitrogenflow were repeated three times. 0.1 g of AIBN as a polymerizationinitiator was added after elevating to room temperature, the temperaturewas elevated to 60° C. and reacted for 15 hours. This reaction solutionwas poured in 100 mL of isopropyl alcohol to precipitate. A resultingwhite solid was filtrated, and then dried at 60° C. under reducedpressure to yield a white polymer.

The resulting polymer was analyzed by 13C, 1H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 6:2,3-epoxypropyl methacrylate ester:styrene 0.3:0.4:0.3

Molecular weight (Mw)=10,4200

Dispersion degree (Mw/Mn)=1.72

This polymer was designated as polymer 13.

Synthesis Example 14

In a 100 mL flask, 9.3 g of monomer 1, 7.4 g of(3-ethyl-3-oxetanyl)methyl methacrylate, 3.1 g of styrene, and 20 g oftetrahydrofuran as a solvent were added. This reaction vessel was cooledto −70° C. under nitrogen atmosphere, and deaeration under reducedpressure and nitrogen flow were repeated three times. 0.1 g of AIBN as apolymerization initiator was added after elevating to room temperature,the temperature was elevated to 60° C. and reacted for 15 hours. Thisreaction solution was poured in 100 mL of isopropyl alcohol toprecipitate. A resulting white solid was filtrated, and then dried at60° C. under reduced pressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 1:(3-ethyl-3-oxetanyl)methyl methacrylate:styrene=0.3:0.4:0.3

Molecular weight (Mw)=8,300

Dispersion degree (Mw/Mn)=1.68

This polymer was designated as polymer 14.

Synthesis Example 15

In a 100 mL flask, 9.3 g of monomer 1, 9.0 g of3-oxo-2,7-dioxatricyclo[4.2.1.0^(4.8)]nonane-9-yl methacrylate, 3.1 g ofstyrene, and 20 g of tetrahydrofuran as a solvent were added. Thisreaction vessel was cooled to −70° C. under nitrogen atmosphere, anddeaeration under reduced pressure and nitrogen flow were repeated threetimes. 0.1 g of AIBN as a polymerization initiator was added afterelevating to room temperature, the temperature was elevated to 60° C.and reacted for 15 hours. This reaction solution was poured in 100 mL ofisopropyl alcohol to precipitate. A resulting white solid was filtrated,and then dried at 60° C. under reduced pressure to yield a whitepolymer.

The resulting polymer was analyzed by ¹³C, 1H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 1:3-oxo-2,7-dioxatricyclo[4.2.1.0^(4.8)]nonane-9-ylmethacrylate:styrene=0.3:0.4:0.3

Molecular weight (Mw)=8,600

Dispersion degree (Mw/Mn)=1.72

This polymer was designated as polymer 15.

Synthesis Example 16

In a 100 mL flask, 9.3 g of monomer 1, 7.8 g of(7-oxanorbornane-2-yl)methyl methacrylate, 3.1 g of styrene, and 20 g oftetrahydrofuran as a solvent were added. This reaction vessel was cooledto −70° C. under nitrogen atmosphere, and deaeration under reducedpressure and nitrogen flow were repeated three times. 0.1 g of AIBN as apolymerization initiator was added after elevating to room temperature,the temperature was elevated to 60° C. and reacted for 15 hours. Thisreaction solution was poured in 100 mL of isopropyl alcohol toprecipitate. A resulting white solid was filtrated, and then dried at60° C. under reduced pressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 1:(7-oxanorbornane-2-yl)methyl methacrylate:styrene=0.3:0.4:0.3

Molecular weight (Mw)=8,300

Dispersion degree (Mw/Mn)=1.76

This polymer was designated as polymer 16.

Synthesis Example 17

In a 100 mL flask, 9.3 g of monomer 1, 11.3 g of2-(4,8-dioxa-5-oxotricyclo[4.2.1.0^(3.7)]nonane-2-yloxy)-2-oxoethylmethacrylate, 3.1 g of styrene, and 20 g of tetrahydrofuran as a solventwere added. This reaction vessel was cooled to −70° C. under nitrogenatmosphere, and deaeration under reduced pressure and nitrogen flow wererepeated three times. 0.1 g of AIBN as a polymerization initiator wasadded after elevating to room temperature, the temperature was elevatedto 60° C. and reacted for 15 hours. This reaction solution was poured in100 mL of isopropyl alcohol to precipitate. A resulting white solid wasfiltrated, and then dried at 60° C. under reduced pressure to yield awhite polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer1:2-(4,8-dioxa-5-oxotricyclo[4.2.1.0^(3.7)]nonane-2-yloxy)-2-oxoethylmethacrylate:styrene=0.3:0.4:0.3

Molecular weight (Mw)=8,300

Dispersion degree (Mw/Mn)=1.69

This polymer was designated as polymer 17.

Comparative Synthesis Example 1

In a 100 mL flask, 9.9 g of 2,3-epoxypropyl methacrylate ester, 3.1 g ofstyrene, and 20 g of tetrahydrofuran as a solvent were added. Thisreaction vessel was cooled to −70° C. under nitrogen atmosphere, anddeaeration under reduced pressure and nitrogen flow were repeated threetimes. 0.1 g of AIBN as a polymerization initiator was added afterelevating to room temperature, the temperature was elevated to 60° C.and reacted for 15 hours. This reaction solution was poured in 100 mL ofisopropyl alcohol to precipitate. A resulting white solid was filtrated,and then dried at 60° C. under reduced pressure to yield a whitepolymer.

The resulting polymer was analyzed by ¹³C, 1H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

2,3-epoxypropyl methacrylate ester:styrene=0.7:0.3

Molecular weight (Mw)=9,800

Dispersion degree (Mw/Mn)=1.81

This polymer was designated as comparative polymer 1.

Comparative Synthesis Example 2

In a 100 mL flask, 11.3 g of monomer 5, 5.7 g of 2,3-epoxypropylmethacrylate ester, 3.1 g of styrene, and 20 g of tetrahydrofuran as asolvent were added. This reaction vessel was cooled to −70° C. undernitrogen atmosphere, and deaeration under reduced pressure and nitrogenflow were repeated three times. 0.1 g of AIBN as a polymerizationinitiator was added after elevating to room temperature, the temperaturewas elevated to 60° C. and reacted for 15 hours. This reaction solutionwas poured in 100 mL of isopropyl alcohol to precipitate. A resultingwhite solid was filtrated, and then dried at 60° C. under reducedpressure to yield a white polymer.

The resulting polymer was analyzed by ¹³C, ¹H-NMR and GPC, and thefollowing results were obtained.

Polymerization ratio:

monomer 5:2,3-epoxypropyl methacrylate ester:styrene=0.3:0.4:0.3

Molecular weight (Mw)=9,600

Dispersion degree (Mw/Mn)=1.73

This polymer was designated as comparative polymer 2.

[Preparation of Resist Lower Layer Film Composition]

A resist lower layer film composition (Examples 1 to 18, ComparativeExamples 1 and 2) was each prepared by dissolving the polymerrepresented by the polymers 1 to 17 or the polymer represented by thecomparative polymers 1 and 2, the acid generator represented byfollowing AG1, AG2 or PAG1 and the crosslinking agent represented byfollowing CR1 in the organic solvent containing 0.1% by mass of FC-4430(manufactured by Sumitomo 3M.) at ratios shown in Table 1, andfiltrating through a filter having a pore size of 0.1 μm and made from afluorine resin.

A solution of each resist lower layer film composition (Examples 1 to18, Comparative Examples 1 and 2) prepared above was applied onto asilicon substrate and baked at 200° C. for 60 seconds to form a resistlower layer film (antireflection film) having a film thickness of 80 nm.

After forming the resist lower layer film, a refractive indexes (n andk) at an wavelength of 193 nm was measured using a variable incidentangle spectro-ellipsometer (VASE) supplied from J. A. Woolam Corp., andthe results were shown in Table 1.

TABLE 1 Acid Crosslinking Polymer generator agent (parts by (parts by(parts by Organic solvent Refractive Refractive mass) mass) mass) (partsby mass) index n value index k value Example 1 Polymer 1 AG1 — PGMEA1.63 0.31 (100) (7.0) (2000) Example 2 Polymer 2 AG1 — PGMEA 1.63 0.33(100) (7.0) (2000) Example 3 Polymer 3 AG1 CR1 PGMEA 1.62 0.31 (100)(7.0) (25) (2000) Example 4 Polymer 4 AG1 CR1 PGMEA 1.65 0.32 (100)(7.0) (25) (2000) Example 5 Polymer 5 AG1 — PGMEA 1.57 0.21 (30) (7.0)(2000) Polymer 1 (70) Example 6 Polymer 6 AG1 — PGMEA 1.65 0.30 (100)(7.0) (2000) Example 7 Polymer 7 AG1 — PGMEA 1.75 0.31 (100) (7.0)(2000) Example 8 Polymer 8 AG1 — PGMEA 1.61 0.29 (100) (7.0) (2000)Example 9 Polymer 9 AG1 — PGMEA 1.59 0.30 (100) (7.0) (2000) ExamplePolymer 10 AG1 — PGMEA 1.64 0.31 10 (100) (7.0) (2000) Example Polymer11 AG1 — PGMEA 1.64 0.30 11 (100) (7.0) (2000) Example Polymer 12 AG1 —PGMEA 1.64 0.30 12 (100) (7.0) (2000) Example Polymer 2 AG2 CR1 PGMEA1.54 0.28 13 (100) (7.0) (25) (2000) Example Polymer 13 AG1 — PGMEA 1.640.30 14 (100) (7.0) (2000) Example Polymer 14 AG1 — PGMEA 1.63 0.30 15(100) (7.0) (2000) Example Polymer 15 AG1 — PGMEA 1.63 0.32 16 (100)(7.0) (2000) Example Polymer 16 AG1 — PGMEA 1.65 0.29 17 (100) (7.0)(2000) Example Polymer 17 AG1 — PGMEA 1.64 0.29 18 (100) (7.0) (2000)Comparative Comparative PAG1 — PGMEA 1.72 0.35 Example 1 Polymer 1 (6.6)(2000) (100) Comparative Comparative PAG1 — PGMEA 1.66 0.32 Example 2Polymer 2 (6.6) (2000) (100)

In Table 1, respective compositions are as follows.

Polymers 1 to 17: from Synthesis Examples 1 to 17

Comparative polymers 1 and 2: from Comparative Synthesis Examples 1 and2

Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)

Crosslinking agent: CR1 (see the following structural formula)

Acid generators: AG1 and AG2 (see the following structural formulae)

Acid generator: PAG1 (described later)

As shown in Table 1, in Examples 1 to 18, n value falls within the rangeof 1.5 to 1.8 and k value falls within the range of 0.2 to 0.45 in therefractive index of the resist lower layer film, and particularly it hasbeen found that the resist lower layer film has the optimal refractiveindex (n) and extinction coefficient (k) enough to exert the sufficientantireflection effect at a film thickness of 30 nm or more.

[Evaluation of Dry Etching Resistance]

In tests for evaluating the dry etching resistance, the solution of eachresist lower layer film composition (Examples 1 to 18, ComparativeExamples 1 and 2) prepared above was applied onto the silicon substrateand baked at 200° C. for 60 seconds to form a resist lower layer filmhaving the film thickness of 150 nm.

This resist lower layer film was etched in CHF₃/CF₄ gas using a dryetching apparatus TE-8500P manufactured by Tokyo Electron Ltd., and afilm thickness difference before and after the etching was calculated.The obtained results are shown in Table 2.

Etching conditions are as follows

-   Chamber pressure: 40.0 Pa-   RF power: 1,300 W-   Gap: 9 mm-   CHF₃ gas flow: 30 mL/minute-   CF₄ gas flow: 30 mL/minute-   Ar gas flow: 100 mL/minute-   Time period: 20 seconds

TABLE 2 Film thickness difference Resist lower layer by CHF₃/CF₄ etchingfilm (nm) Example 1 71 Example 2 75 Example 3 80 Example 4 60 Example 570 Example 6 74 Example 7 76 Example 8 85 Example 9 78 Example 10 80Example 11 88 Example 12 68 Example 13 75 Example 14 70 Example 15 75Example 16 77 Example 17 76 Example 18 79 Comparative 48 Example 1Comparative 52 Example 2

As shown in Table 2, it has been found that the resist lower layer filmof the present invention has the feature that the etching speed is fast.

[Evaluation of Resist Patterning]

A solution of an ArF monolayer resist composition was prepared bydissolving an ArF monolayer resist polymer 1 in the organic solventcontaining 0.1% by mass of FC-4430 (manufactured by Sumitomo 3M.) atratios shown in Table 3, and filtrating through the filter having thepore size of 0.1 μm and made from the fluorine resin.

TABLE 3 Acid Basic Organic Polymer generator compound solvent (parts by(parts by (parts by (parts by mass) mass) mass) mass) ArF ArF monolayerPAG1 Quencher 1 PGMEA monolayer resist polymer 1 (10.0) (1.2) (1800)resist (100) composition

Respective compositions in Table 3 are as follows. ArF monolayer resistpolymer 1 (see the following structural formula)

Acid generator PAG 1 (see the following structural formula)

Basic compound: Quencher 1 (see the following structural formula)

Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)

The solution of the resist lower layer film composition (Examples 1 to18, Comparative Examples 1 and 2) prepared above was applied onto a Sisubstrate and baked at 200° C. for 60 seconds to form a resist lowerlayer film (antireflection film) 80 nm thick. The solution of the ArFmonolayer resist composition was applied onto this resist lower layerfilm and pre-baked at 110° C. for 60 seconds to form a photoresist film150 nm thick. Then, the photoresist film was exposed using an ArFexposure apparatus (manufactured by Nikon Corporation: S307E, NA 0.85, σ0.93, cycle light ⅔, 6% half tone phase shift), baked (PEB) at 100° C.for 60 seconds and developed with the aqueous solution of 2.38% by massof tetramethylammonium hydroxide (TMAH) for 60 seconds to afford apositive type pattern. A sectional shape of the resulting pattern of 80nm lines and spaces was observed. The results are shown in Table 4.

TABLE 4 Resist lower layer film Cross-sectiona shape of photoresist filmExample 1 Rectangular shape, no footing profile Example 2 Rectangularshape, no footing profile Example 3 Rectangular shape, no footingprofile Example 4 Rectangular shape, no footing profile Example 5Rectangular shape, no footing profile Example 6 Rectangular shape, nofooting profile Example 7 Rectangular shape, no footing profile Example8 Rectangular shape, no footing profile Example 9 Rectangular shape, nofooting profile Example 10 Rectangular shape, no footing profile Example11 Rectangular shape, no footing profile Example 12 Rectangular shape,no footing profile Example 13 Rectangular shape, no footing profileExample 14 Rectangular shape, no footing profile Example 15 Rectangularshape, no footing profile Example 16 Rectangular shape, no footingprofile Example 17 Rectangular shape, no footing profile Example 18Rectangular shape, no footing profile Comparative Example 1 footingprofile Comparative Example 2 Rectangular shape, no footing profile

As shown in Table 4, it could been confirmed that an excellent resistpattern having a rectangular shape with no footing profile was formed onthe photoresist film on the resist lower layer film (antireflectionfilm) formed using the resist lower layer film composition of thepresent invention.

The present invention is not limited to the above-described embodiments.The above-described embodiments are some examples, and those having thesubstantially same composition as that described in the appended claimsand providing the similar effects are included in the scope of thepresent invention.

1. A substrate comprising, at least: a resist lower layer film on asubstrate, the resist lower layer film formed from a resist lower layerfilm composition comprising: at least a polymer having a repeating unitrepresented by the following general formula (1),

(wherein R¹ represents a hydrogen atom or a methyl group; R² representsa linear or branched alkylene group having 1-8 carbon atoms; R³represents a hydrogen atom or an acid labile group; and 0<a≦1.0), andfurther containing one or more of an organic solvent, an acid generator,and a crosslinking agent; and a photoresist film formed on the resistlower layer film.
 2. The substrate according to claim 1, wherein theresist lower layer film serves as an antireflection film.
 3. Thesubstrate according to claim 1, wherein the polymer further comprises arepeating unit having a light absorbing group of an aromatic group. 4.The substrate according to claim 1, wherein the acid generator is anammonium salt represented by the following general formula (2),

wherein R^(101d), R^(101e), R^(101f) and R^(101g) each represent ahydrogen atom, a linear, branched or cyclic alkyl, alkenyl, oxoalkyl oroxoalkenyl group having 1-12 carbon atoms, an aryl group having 6-20carbon atoms, or an aralkyl or aryloxoalkyl group having 7-12 carbonatoms where a part of or all of hydrogen atoms may be substituted withan alkoxy groups(s); R^(101d) and R^(101e), or R^(101d), R^(101e) andR^(101f) may form a ring, and when forming the ring, R^(101d) andR^(101e), or R^(101d), R^(101e) and R^(101f) each represent an alkylenegroup having 3-10 carbon atoms or a heterocyclic aromatic ring havingthe nitrogen atom in the formula in the ring; and K⁻ represents anon-nucleophilic counter ion.
 5. The substrate according to claim 2,wherein the polymer further comprises a repeating unit having a lightabsorbing group of an aromatic group.
 6. The substrate according toclaim 2, wherein the acid generator is an ammonium salt represented bythe following general formula (2),

wherein R^(101d), R^(101e), R^(101f) and R^(101g) each represent ahydrogen atom, a linear, branched or cyclic alkyl, alkenyl, oxoalkyl oroxoalkenyl group having 1-12 carbon atoms, an aryl group having 6-20carbon atoms, or an aralkyl or aryloxoalkyl group having 7-12 carbonatoms where a part of or all of hydrogen atoms may be substituted withan alkoxy group(s); R^(101d) and R^(101e), or R^(101d), R^(101e) andR^(101f) may form a ring, and when forming the ring, R^(101d) andR^(101e), or R^(101d), R^(101e) and R^(101f) each represent an alkylenegroup having 3-10 carbon atoms or a heterocyclic aromatic ring havingthe nitrogen atom in the formula in the ring; and K⁻ represents anon-nucleophilic counter ion.
 7. The substrate according to claim 3,wherein the acid generator is an ammonium salt represented by thefollowing general formula (2),

wherein R^(101d), R^(101e), R^(101f) and R^(101g) each represent ahydrogen atom, a linear, branched or cyclic alkyl, alkenyl, oxoalkyl oroxoalkenyl group having 1-12 carbon atoms, an aryl group having 6-20carbon atoms, or an aralkyl or aryloxoalkyl group having 7-12 carbonatoms where a part of or all of hydrogen atoms may be substituted withan alkoxy group(s); R^(101d) and R^(101e), or R^(101d), R^(101e) andR^(101f) may form a ring, and when forming the ring, R^(101d) andR^(101e), or R^(101d), R^(101e) and R^(101f) each represent an alkylenegroup having 3-10 carbon atoms or a heterocyclic aromatic ring havingthe nitrogen atom in the formula in the ring; and K⁻ represents anon-nucleophilic counter ion.
 8. The substrate according to claim 5,wherein the acid generator is an ammonium salt represented by thefollowing general formula (2),

wherein R^(101d), R^(101e), R^(101f) and R^(101g) each represent ahydrogen atom, a linear, branched or cyclic alkyl, alkenyl, oxoalkyl oroxoalkenyl group having 1-12 carbon atoms, an aryl group having 6-20carbon atoms, or an aralkyl or aryloxoalkyl group having 7-12 carbonatoms where a part of or all of hydrogen atoms may be substituted withan alkoxy group(s); R^(101d) and R^(101e), or R^(101d), R^(101e) andR^(101f) may form a ring, and when forming the ring, R^(101d) andR^(101e), or R^(101d), R^(101e) and R^(101f) each represent an alkylenegroup having 3-10 carbon atoms or a heterocyclic aromatic ring havingthe nitrogen atom in the formula in the ring; and K⁻ represents anon-nucleophilic counter ion.